Demonic Spiders/Video Games/Role-Playing Game

If ever there was evidence that game designers hate RPG fans, Demonic Spiders are it.

Baldur's Gate

 * Baldur's Gate II, and many other games based on Dungeons & Dragons, have mind flayers. You really don't want to mess with mind flayers if you have any other choice, as they will cause your party members to start attacking each other—and the ability that causes this is psionic, not magical, so it's really hard to defend against. Liches and dragons are also extremely dangerous, but they tend to be bosses. Note that while you can make yourself immune to their stun/hold/confusion attacks, there is no way to protect yourself from the INT-drain. So even if you do get those spells, you still die if you are hit three times. (or less, if you are particularly low of intelligence).
 * One flayer-killing tactic is to raise undead to block them from getting to you. Another, more effective tactic is to note where the passageways are and fill them up with traps, then choose someone expendable to open the door at the end.
 * Mordenkainen's Sword works wonders against Mind Flawyers, as the swords are immune to the INT-drain.
 * Casting three simple spells on your characters would protect them from 99% of a mind flayer's arsenal, leaving them as slightly squishy monsters for your characters to plow through. Beholders, on the other hand, are extremely dangerous... until you get the Shield of Balduran, which deflects beholder rays back to their source. At which point beholders just become a source of amusement, as you watch them swarm your shield-equipped character and wipe themselves out. The players who don't get the Shield of Balduran, though, are in for a rough fight. Magic is a useful defense against mind flayers, but beholders can dispel the defenses you put up against them in one attack and then kill you the next. Their most deadly attack is a ray that serves as a Flesh to Stone spell. Not only will this end the game if it hits your main character, it will remove any effected character from your party. This isn't a huge deal from a gameplay perspective, as removed characters can just be recruited again when restored. From a roleplaying one, though, it's traumatic; removing a character from your party will instantly end your romance with him or her. You heard me right. Beholders can KILL LOVE.
 * For those who don't have the shield, the easiest way to take down Beholders is to use summoned monsters. Thanks to a quirk in the AI, Beholders don't use their rays on summons and try to bite them instead. While the Beholder is distracted by the summon, your party can hack it to death with minimal fuss.
 * An earlier example would probably be Umber Hulks. They're tough and cast Confusion with unnerving frequency at levels where you might not have the ability to dispel it or the items to protect against it. Once you get Death Spell though they die instantly. By the way, guess which monster type Mind Flayers are usually accompanied by? That's right, lots and lots of Umber Hulks.
 * It should probably be mentioned that BG2 scales it's encounters according to level. The Shadow Dungeon if done at a high enough level contains liches in regular spawns. Spawns which also includes Bone Golems and Vampires.
 * If you don't have powerful enough magic weapons, we'd strongly advise against wandering the streets of Amn at night, because you will meet a vampire, and it will kill you. Their level drain and Dominate effects are also hugely annoying.
 * In the first game Kobolds. The Commandos anyway. Thanks to their habit of showing up in significant numbers, blocking chokepoints, bringing along plenty of other Kobolds as meatshields, and packing fire arrows which are absolutely deadly in a low level campaign like this one. They also show up early enough that you probably won't have anyone who can use spells like Fireball and Cloudkill. If your main character is a Squishy Wizard or Glass Cannon thief w/o adequate missile protection and/or fire resistance and the Commandos spot him/her, it's pretty much game over. Even worse, there's a thankfully optional dungeon where Kobold Commandos endlessly respawn -- and it's mostly tight corridors that favor them and are bad news for a melee oriented party. Did I mention they also give paltry experience when slain? In the sequel they aren't as bad since they don't show up as often and your characters are beefier.
 * Another one from the first game: If you ever got caught stealing or had low enough reputation that they'd attack automatically, the Flaming Fist Enforcers would ruin your day.
 * Most of the different types of golems in the 2nd game can be defeated with minimal fuss. Stone golems are pushovers. Clay golems are even easier as long as you don't forget blunt weaponry (they resist everything else). Iron golems are bit beefier and have a nasty poison attack, but they are still managable. The Adamantite golems that show up when your party is higher level are another matter. These beasts don't rely on any special tricks -- they are just huge powerful bruisers that resist damn near everything and can't even be scratched by anything weaker than +3 weapons. All you can do is buff up your melee characters and pray to the random number god. Adamantite golems are usually accompanied by other golems too.
 * Enemy mages are also fairly nasty to face, especially if they have friends. A single Confusion can cause your entire group to self-destruct as the frontline fighters arbitrarily decide they'd like to massacre the missile support rather than fight their actual enemies, meaning you get torn limb from limb by the mages' friends. And they usually turn up with a Contingencied Protection from Anything Short Of An Angry God combo, meaning that as soon as a fight breaks out they become almost impossible to hurt. Entire fights can boil down to whether or not Jaheira has Insect Plague.
 * In the first game, Sirines cast dire charm on your party and shoot you with poison arrows. Oh and they always come in groups.

Dragon Quest

 * Many of Dragon Quest's Elite Mooks fit this: for example, the Demon Knight, who packs a heavy punch, is immune to magic, and has supreme dodging skills (real Nightmare Fuel those are); the Magiwyvern, who has a tendency to bludgeon you to death in your sleep; the Starwyvern, who has deadly flame breath, high HP and attack power, and Healmore (better use Stopspell and hope it works); Wizards, who possess Sleep and Hurtmore (potential One-Hit Kill) and are resistant to magic; and the Nigh Invulnerable Armored Knights (they have both Healmore and Hurtmore); and Red Dragons in the lower levels of The Very Definitely Final Dungeon. Red Dragons are the worst of the Elite Mooks, as they have both Sleep and Healmore, and do the worst melee and fire breath damage out of all the monsters bar the Dragonlord himself.
 * To make things even worse, by the time you face these guys, you're trying to save HP and MP for the big Dragonlord showdown, which means you cannot afford to waste time and magic fighting the Elite Mooks and you pretty much have to run from every one of them you encounter. Except sometimes you don't have the option—sometimes they'll ambush you and get in a free attack (usually Sleep or a nasty attack), or you'll get the dreaded "blocked in front" message if you try to run, leaving you open to the aforementioned free attack. Worst of all, the final bridge and marsh stretch before you enter the Dragonlord's great hall is CHOCK FULL of these things, and oftentimes just after you succeed in running from one of them, another will pop up before you've taken more than five steps, and any one of them could be the one that won't let you run. Good luck— you'll need it!
 * The various enemies in Dragon Quest VIII shaped like bells can not only level themselves up repeatedly, but call in reinforcements...who immediately call in more reinforcements that call in even more until you're dealing with 8 of them, at which point they unleash an attack that INSTANTLY KILLS YOUR ENTIRE PARTY. (How appropriate that said attack is to chime out the Game Over music from DQ1.)
 * Dragon Quest II has several, but the most infamous example has to be the Gold Batboons/Bat Demons in the final area of the game. Those babies could potentially wipe out your entire party in one turn with their Sacrifice spell.
 * Dragon Quest III' introduced the Man Eater Chests to the series (and later on in the same game, the upgraded Mook, the Mimics). The lesser can inflict terrible blows, hits like a freight train and can make your allies fall asleep by emitting sweet breath. The Mimics, however, can kill your party members with Defeat. It can also make you fall asleep and it can also leech magic points from you to it. Moreover, the Mimic chests attacks twice in one turn. Have fun!
 * Dragon Quest IX has the Boa Bishops, which persistently chase you down, have a large hitbox, and always spawn on top of you- and that's BEFORE you actually start the battle. In battle, they can attack twice, which they use to their advantage by activating an ability that always makes your characters fall asleep (even with maximum resistance to sleep) and then follow up with a tidal wave attack that does severe damage to the whole party. They also have Omniheal and tend to come in groups of two or three. Thank goodness they're vulnerable to Whack.
 * Dragon Quest V has the Evil Masters and Red/Blue Eaters. Eaters come in large groups and have high agility and ridiculously strong attacks. Evil Masters can summon a lot of these, and worse, if an Evil Master defends instead of attacking, another goddamn Evil Master shows up right then and there, and unlike most reinforcements, has an instant turn.

EarthBound

 * EarthBound has the Dali's Clock, which can attack you and freeze time in mid-hit, causing a long string of attacks.
 * Everything in the Department Store and Moonside is a Demonic Spider. The Enraged Fire Plug, the aforementioned Dali's Clock, and the infamous Cracked Coffee Cup are the worst, but the Mystical Record and the Musica aren't fun either.
 * Not to mention the Ghost of Starman. They cast Psi Starstorm Alpha at the start of every fight, which can kill three members of your party at once, and they travel with the Final Starman, which is a Boss in Mook Clothing.
 * EarthBound also has the Demonic Petunia in Deep Darkness. Its only attack (a "giant blast of water" that is actually a PSI Fire Gamma spell) will hit all your party members for a ton of damage (unless you're protected against it).
 * There's also the Atomic Power Robot. It can freely use the "replenish a fuel supply" action (which heals whatever it's used on fully), and it explodes upon defeat. Not to mention it shows up in the area where you can get the Sword of Kings. If you want it, you will almost definitely be fighting a lot of battles, which means a lot of chances for these guys to join said battles and screw you over. You can, however, use the Mirror ability on them, letting Poo refuel your own party to full health. Don't think about how that works.
 * Then there are the Loaded Dice. They show up in an area where you only have one controllable character. Their only action is to call for help, which if successful will summon another enemy into the battle. Considering your small party when fighting them, this can rapidly get out of hand if the Loaded Dice are not defeated quickly.
 * "The Territorial Oak burst into flames!"
 * Mobile Sprouts aren't too hard to kill, but then they plant seeds and grow several more Mobile Sprouts, which plant even more seeds, which causes the situation to rapidly escalate beyond your control. Unless you have enough PP to hit them with PSI Rockin' Alpha, you could be in trouble.
 * Mother 1 has too damn many of these, especially in the last area of Mount Itoi due to bad programming. The one that immediately jumps to the forefront is Juana: it can deal 150 HP of damage with every regular attack if you're not using a shield, and it also comes with PK Thunder Gamma, PK Fire Beta, and PK Fire Gamma, which hit all party members. It uses PK Beam Gamma, which kills anyone not wearing a Franklin Badge. To top that all off, it can raise its defense to impervious levels with its "darling smile." It's bad enough alone, but it occasionally shows up with a Super Energy Robot (called SuperEnergy due to character constraints on the NES), which can heal an enemy completely. Your best bet is to run away when you see one unless you're traveling with.
 * Mother 3 has Trees, which take the worst qualities of the Woodohs from MOTHER 1 and the Territorial Oaks from EarthBound. Not only do they explode, but they can summon MORE of themselves, and at the point in the game where you encounter them, you can very easily die from the flames if you aren't quick and are low on health.
 * Almost everything in the Volcano level is some form of this. The Ms. Lavas will hit you with PK Fire Gamma for around 100 damage per party member, the Pyreflies are weak but fast and good at whittling your health down, and the Magmen have a tremendously powerful 'eruption' attack and can spawn Pyreflies. There's a reason they sell Flame Pendants in Saturn Valley.
 * Men's Room Signs? Okay, they're really out of ideas now - The Men's Room Sign used PK Starstorm! ...what.

Etrian Odyssey

 * The DS game Etrian Odyssey can have some Demonic Spider moments, especially trying to level low level characters solo on the first floor. On occasion you will find a Treerat, indistinguishable from other Treerats, that can call for allies and succeed without fail, and these reinforcements also call for back up. To make matters worse, this usually happens before you can regularly kill them with a single hit, and long before you get any abilities to hit all enemies. Your only options are to run away, waste all the time and items invested in winning and receive no experience, or die and face a game over, losing that much more progress. Now combine the idea of Demonic Spider with That One Boss into an independently moving, player hunting entity known more simply as F.O.E. that can randomly interject its own brand of instant game over by joining into any battle mid fight, usually by killing everything else on the field before it lays into your party, who are more often than not vastly unprepared no matter what you do unless you happen to be roughly 8-14 levels over the standard level range for the floor you're on, or following a very specific leveling guide for maximum optimization builds.
 * Really, Etrian Odyssey is basically made of demonic spiders. One thing that tends to stick to players' minds is the Gigaboars, since it's the stopping point for many in the second stratum, forcing a serious training and reequipping stop. See, the Gigaboars don't have much HP, all in all—180 is a pretty manageable amount for a party in that level. But they hit like mack trucks. As in, if you're using a Ronin or War Magus in the frontlines? Oneshotted. And they have pretty decent speed too, so you can't use the most damaging attacks, since they're slow and you'll give them the first action that way.
 * In the second stratum, you run into the flower-like Petaloids. They have an ability called Sleeper, which can (and often times, does) put your entire party to sleep, leaving you unable to act. They're bad in the second stratum, but near the end of the normal game, when you encounter 2 much stronger versions of them with enemies that can two-shot most of your party, you begin to get very scared of them.
 * Another star in the ending of the second Stratum is the Poseidon. A huge grass brachiosaur with about double the HP of almost everything else in the floor, which doesn't hit for all that much less than the areas F.O.E.s, and which has a move named Scurry that hits your whole party - yes, including the SquishyWizards in your back row - for huge damage. Additionally, it seems fond of blindsiding you (which poses the question of how in blazes you get blindsided by a goddamned Brachiosaurus), which means he gets a free turn to maul you into paste. And he almost never appears alone, to add insult to injury. Good luck avoiding them, since all resource-gathering points have a random chance of giving you a battle instead of an item. Oh, and these battles are usually made up of the strongest monsters in that entire wing of the dungeon. Imagine picking flowers on Floor 6 only to be ambushed by two Poseidons, who proceed to Scurry the party to death. Even if you survive the battle, you will lose an opportunity to gather items, as you can only do so a certain number of times per day, and the ambush counted. The third game does not count an ambush as gathering items, however.
 * The third stratum of the second game has some wicked FOEs. The Helldra can wipe your entire party out in one or two hits. They only move around the map at night, but one of the (required) missions and most of the paths on the last floor of the stratum require it to be nighttime. And God help you if you get into a fight in the wrong place, otherwise a Giant Enemy Crab known as "Killclaw" will appear from thin air to mess you up; some parts of the map even have two or three Killclaw spawn points right next to one another. If you get into a fight with multiple Killclaws and you can't slay them fast enough, they will continuously respawn as long as you're in battle. Oh, and of course the Helldra gets a Palette Swap in the next strata, who blocks your path unless it's nighttime, in which case it doggedly pursues you. The normal options to stun or distract FOEs don't work on Helldra or its kin.
 * When Helldra palette swaps into Evildra, it becomes Nightmare Fuel. The scales go from purple to a poisonous green while the eyes turn demonic red. The heads have a more intelligent expression, so you know that it knows that you will die.
 * The Great Lynx at the beginning of the third game. It appears in the first stratum if you stray too deep, and if you're a low level, it'll be faster and stronger than anything you have in your party. In that same vein, the Largebill, which appears in the second floor of the first stratum during the day, and is the reason you'll be doing most of your exploration during the night early-game.
 * Golden Idols from The Drowned City. They have insurmountable defense that turns anything that isn't an Ice attack into Scratch Damage, and they're fond of Breath, which causes petrification and hits the whole party. If they manage to petrify your Zodiac or Monk, you're screwed.
 * Venomflies from The Drowned City. They spend a turn inflicting poison on one character. Then the poison kills that character in one turn. Pain.

Fallout

 * The Fallout series has at least one enemy in each game that is guaranteed to lay a smackdown on your post-apocalypse scavenger ass. Deathclaws are the most well known of these radioactive abominations: in 1 and 2, they were merely superhumanly fast, brutish, and damaging. In 3, though, they gain some fantastically cheap moves, including the ability to leap from normal maximum effective shotgun range to into melee within a split second, while taking more punishment than a Super Mutant to kill. They can also take out a character with full health and the best non-power armor in a couple of swings. Best of all, they can be encountered in packs. The reason for this is cheap, though. The Deathclaw's attacks bypass DR and deal full damage to the player every time. However, if you can kill a Deathclaw, you can make a melee weapon which does the exact same thing-- by mounting its claw to a glove on your hand. Sneak attacks and the Dart Gun-- a weak weapon that cripples targets' legs so they go slower and can't perform "leaping" type attacks-- are very useful for taking them out. With Better Criticals, you can kill one in 2-4 shots from Lincoln's Repeater, fewer if you use more powerful things like Fat Man or the like.
 * In Fallout: New Vegas, Deathclaws take advantage of the new Damage Threshold system to take Made of Iron to a new level. As in, using the anti-materiel rifle with AP rounds on a sneak critical (something that would gib practically anything else) knocks off maybe half their health. God help you if you wander into the Deathclaw Promontory or Quarry Junction at a low level.
 * Fortunately, if you can cripple the Deathclaw's leg, it can be easy enough to, literally, keep out of arm's reach, as long as there isn't more than one coming at you, all you need to do against a crippled Deathclaw is keep your distance while shooting, and hope you don't have your back to a wall...
 * In Fallout 3, what you really need to watch out for are the Albino Radscorpions and Super Mutant Overlords of the Broken Steel expansion. The Albino Radscorpions are 1.5 times as large as the 2nd largest Radscorpions, have as much health as a Super Mutant Behemoth, and are random encounters in groups of 1-3. Overlords spawn anywhere with Super Mutants, carry Laser Shotguns which punch straight through power armour due to a hax effect that does unblockable 40 HP damage when used on the player. The shotgun fires 3 beams. Either that, or it comes with a Gatling Laser or a Super Sledge. Its health is a touch less than a Behemoth, but has higher endurance, and unlike the finite Behemoths, Overlords respawn. If you have the Chinese Stealth Armor and Silent Running perk, the easiest way to get rid of Overlords is to sneak behind them and drop a grenade or mine in their pants (by reverse-pickpocketing them to their inventory). This should kill them without fail.
 * Feral Ghoul Reavers from the same game share none of the weaknesses of the Overlords and Deathclaws and share the "may spawn whenever enemies of the same type may spawn". Dart guns only prevent their leap attack and cut their terrifying movement speed to 75% while not stopping them from hitting you VERY hard. They have insane perception that they will see you without fail even with 100 sneak, silent running perk, and Chinese Stealth Armor, making sneak attacks on them nigh impossible; they lack any weapons to shoot off, manage to have a ranged attack other Feral Ghouls lack, and share the 1200+ HP and 10 Endurance that Overlords have. For icing on the cake, Reavers can get bugged in mid-fight, turning them invincible for some time.
 * Feral Ghoul reavers also have a long ranged, accurate and high damage ranged AOE attack that can easily kill you while you try to sniper duel them
 * Of the three, only the Super Mutant Overlords give any loot worthy of the ammo expended to kill them. The other 2 give a few hundred bottlecaps at most
 * The Pitt Expansion Pack features Trogs as a replacement for Super Mutants. In practice, they more closely resemble weaker Deathclaws. Unfortunately for the player, they tend to come in packs of eight or more at times, and a higher-level player will encounter Trog Savages, which are every bit as strong as actual Deathclaws. To add further injury to injury, you can't bring in your Powered Armor or Frickin' Laser Beams, so higher-level players are going to end up with a much tougher time.
 * Fallout Tactics has one special encounter with a huge pack of Deathclaws that takes place in complete darkness. Also, burst weapons in the series are famously unreliable against anything with decent armour. Quite a few of the robots in the same game are nearly invincible against anything except Energy Weapons, but the Behemoth Droid is perhaps the worst, given how well it is armed.
 * In Fallout 2, we have the Bounty Hunters. They are probably as bad as Deathclaws, or worse. Why? Because if your character is a child killer or just too damn evil, these guys attack you. Until the end game, they ALWAYS outgun you, using weapons you are only going to see somewhere further in the game. They also always outnumber you. This only gets worse as the game advances, and every one you kill drops your karma further, so even more powerful (relative to your level) mercs come after you next time if you happen to be on one of the karma "borders" the game seems to use for these encounters.
 * The Wannamingos in Fallout 2 are quite deadly foes, especially if you're unfortunate enough to take the wrong entrance to the Redding mine, and encounter the "boss" wannamingo first. It doesn't help that it's hard to figure out what parts of their anatomy are comparable to those of humanoids. Not to mention that some weapons which are otherwise quite useful at this stage in the game are about as much use as a chocolate teapot against Wannamingos. In the Redding mines with an assault rifle? Time to find an earlier savegame.
 * The expansion pack Point Lookout adds in Swampfolk and Tribals. Despite wielding old-timey double barrelled shotguns or axes, and wearing overalls or robes, they are tougher than Enclave goons wielding plasma rifles and wearing high-tech powered armor, and are about as common as regular raiders in the swamp. Oh, and there's reavers in the swamp. The next expansion, Mothership Zeta adds space aliens, whom, to be honest, are beat than the frickin' hillbillies with their axes.
 * Even the toughest enemies in Fallout are no mach for a sneak attack with a well placed bottlecap mine and a high explosives skill.
 * Fallout: New Vegas has Cazadores, giant mutant wasps that despite their flimsiness, attack insanely fast and usually come in large packs. And their poison attack can quickly kill the more unaware player (or those without Antivenom). For added Nightmare Fuel, the loud sound that a Cazador makes upon stinging a target is bugged, such that it plays at full volume regardless of how far away it is (as long as it is actually being rendered by the game), and regardless of who its target is. Thankfully, due to the small DT stat they have, a 10mm SMG with hollow-point (standard or jacketed HP) will tear them to pieces. Or you could shoot their wings out. Of course, this only really works if they're in front of you. The little bastards have a habit of being everywhere. And the larger Cazadors need more than just a shot in the wings to kill: first you have to cripple their wings, then cripple their legs, and then FINALLY put enough rounds into their skull to kill them.
 * Trying to get the Ratslayer at a low level? Have fun finding out Giant Rats are not easy pickings like they are in most RPGs. Here, they're fast, tenacious, and can chew through Metal and Combat Armor with ease.
 * If you're at a high level, you better not piss off any of the major factions. You'll get hit squads after you armed with chainsaws, 12.7 mm SMGs, and anti-materiel rifles.
 * And the radscorpions are still around, of course. Giant radscorpions, in particular. You know it's bad when you're faced with an oversized arachnid and breaking out the ap ammo is a sound survival strategy, rather than an exercise in hilarious overkill. The locations where these guys are mixed in with their fast, sneaky bark scorpion cousins are especially... interesting.
 * And, if you think Giant Radscorpions are tough, Old World Blues gives us Robo Scorpions. These things are even tougher, can shoot laser from their tails, and if you think you had it, it will blow up after you finally defeat it.

Mass Effect

 * Mass Effect has a few of these. In the first game we have the Geth. They're a race of Mecha-Mooks, until you get to higher levels and encounter Destroyers, Hunters, Primes, and Juggernauts. Then there are the Krogan, which are damage sponges that aren't exactly a picnic to fight. The second game has the Collectors's special classes, which include Assassins and Guardians. The Man Behind the Man can also control one at a time, which might cause the player to have an Oh Crap moment when the words "Assuming control" are heard. This not only fully recharges the possessed Collector's barriers but also adds ANOTHER layer of shielding and gives the possessed Collector the ability to spam biotic attacks that knock you out of cover and rip your shields apart. And the Collector constantly tries to rush you and knock you out of cover.
 * The biotic attacks from the first game do very little damage, but ignore shields and almost always knock you to the ground for several seconds, during which you can't even pause the game. This is painful when it happens during a heated fire-fight, but worst when you're surrounded by nothing but biotics, who whittle your health down over two minutes while you wait for the game to allow you to access the menu.
 * The sequel turns Husks into these. For those not in the know: Mass Effect 2 Husks are fast-moving cybernetic zombies that tend to move in erratic patterns (making it hard to hit them) have Armor at higher difficulties (increasing the damage they can take and making them immune to many of your powers) and attack you in melee (which knocks you back and makes you unable to act for a second) in groups of a dozen or so (which staggers their melee attacks and, by extension, stun-locks you) usually backed up by either Collectors (which will shoot you to death), Scions (which shoot you with a BFG that kills your shields and knocks you out of cover so they can shoot you to death) or Praetorians ("whats this, you've taken away my first layer of defense? We can't be having THAT, can we?").
 * Mixed in a swarm of Husks in the second game will be one or two or more Abominations. Abominations are exactly like Husks...except that they explode when they die. And, of course, that takes away quite a bit of health. So, while you're being swarmed by Husks on all sides, you're trying to move away from the Abominations so you can kill them without being hit with... whatever exploding robot zombies are made of.
 * The Thorian Creepers in the first game were every bit as bad, especially as the mission where they are really swarming you is in a series of cramped corridors. The worst part is that they deal toxic damage, which completely ignores your shields. If you're playing a character with Immunity, this isn't so bad, but otherwise you're in for a world of hurt as they swarm you by the dozen and cover you in toxic vomit.
 * Krogan. Insanely tough, generally have Immunity (dramatically reducing the damage they take from your weapons), sometimes have Biotics abilities, and they love to charge you at insane speeds and get into melee range, where they can typically beat you to death in a couple of quick and painful blows. Oh, and if you kill them, they simply fall over, auto-heal all their damage, and get back up for another go.
 * Almost as bad are the Rocket Drones. Tough to kill and with an attack that deals massive damage. Also, immune to most biotic abilities. Not too bad in open areas, but the Luna mission has you fighting them en masse in very cramped quarters. Your best friend for that mission is Tali (with possibly Garrus or Kaidan as backup). Overload, Sabotage, and AI Hacking should shut down those drones quite handily, especially if you let them bunch up in the hallway where a single Sabotage will knock out a half-dozen drones' weapons at once.
 * Geth snipers. They can one-hit kill you without effort on Hardcore, to say nothing of Insanity. Ditto for Geth Ghosts, which are basically the same as snipers, except that they are smaller, never ever stay still, and have a terrible habit of jumping onto the wall or ceiling over your cover to get a clear shot at you.
 * In Mass Effect 2, the Geth Snipers are gone, but in their place, something much nastier: Scions. They have skin so thick it takes dozens of fully-upgraded sniper bullets to bring them down (and only two classes start the game with a Sniper Rifle). While they are slow, they have an area-of-effect attack which brings you from healthy to half-way-dead in one shot, and they never attack alone. Oh, and that attack? Almost impossible to avoid and bypasses most things you can take cover behind. But good luck telling that to your teammates, who still huddle desperately to that wall as their HP is depleted in seconds. Seems you'll have to take that wave of enemies on your own now.
 * Go to Korlus on Insanity difficulty, especially early in the game. It's really hard, but not egregious until the end boss fight. Can you say Krogan flunkies?!
 * Insanity even turns vorcha into these, since almost all enemies on Insanity have some form of special defence, and even worse their regeneration can mean that you can take a vorcha mook to 1 percent, have to change heatsink clips, and by the time you've reloaded, the vorcha has already healed back to max.
 * Anything with a flamethrower. Getting shot by one causes Shepard to flail around, trying to put out fires on his/her armor. While you're flailing, you can't move, meaning whatever shot you is just going to get closer and shoot you again, stunlocking you to death.
 * Oh, and it promises to get even worse in Mass Effect 3, judging from screenshots. Say hello to the Reapers' newest weapon;  Krogan Husks!
 * In the multiplayer demo: Cerberus Phantoms. Described as "Ninjas on speeds", they are fast moving melee flankers with biotic barriers that like to jump around and use cloaking devices to avoid bullets from long range. They prefer to get up close so they can chop you and your squadmates into pieces with their katanas. A few strikes from a Phantom's katana can easily kill even a fully shielded krogan. If standing still, the Phantom can grapple you for an instant kill, from which you cannot be revived. And although they are fragile alone (though their barriers can make up for that), they spawn in the heat of battle, while you are busy shooting at the rest of the advancing Cerberus troopers, quietly entering the flanks to drive you and your squad from cover in the best case, or single-handedly causing a Total Party Kill in the worst. So when you hear a player cry "PHANTOM!", target and kill them with extreme prejudice from long range, or chances are that someone in your squad may be seeing the Incapacitated screen/Spectator's screen very soon.
 * And to make matters worse, Phantoms will usually be covered by Nemesis', snipers capable of taking down your shields in a single hit, leave you open for the Phantom to slice you to pieces.
 * Even worse still: Phantoms will occasionally use a Nemesis as bait. Nemeses are powerful long range snipers, but they are completely helpless in close range because they lack a close range or melee attack. Phantoms know that you know that. So they stay close to a Nemesis, waiting for you to engage her in melee and jump you out of a corner you didn't see.
 * Turrets. Dropped by combat engineers, these are capable of shredding a player's shields to nothing in the blink of an eye. Engineers love to drop them in places where they can cover multiple choke points, and they sport both Shields and Armour, making them very tedious to kill.
 * Marauders become this on the higher difficulties. Their Phaeston rifles are lethally accurate, cutting through your shields like butter and slashing your vulnerable body apart during your stun animation. In groups, two of them will pin you down while a third flanks you and punches through your shields, knocking you into the fire of the other two. Oh, and they often appear with Cannibals, which will launch grenades over your cover, leaving you open to the Marauder's fire.
 * Banshees, banshees, BANSHEES! Ridiculously tough, can Teleport Spam, throw nearly undodgeable biotic attacks that can kill you in two or three hits... and have an instant death attack if they manage to get within melee distance. In multiplayer, you cannot be revived if you get hit with this. The scream of a Banshee is the signal that the battle is going to get ugly, fast.
 * 3 also introduces us to the greatly buffed Geth Hunters. Unlike in 2, they turn completely invisible now, and stay invisible until their shields are destroyed. If you miss the slight distortion their invisibility makes, they will get up close, uncloak, and hit you with their plasma shotguns, destroying your shield and probably doing a fair amount of damage as well. Even worse, they like to sneak up on your while you're dealing with Pyros or Primes.

Shin Megami Tensei

 * In the Shin Megami Tensei series, any enemy can be a Demonic Spider if they have an attack that any of your characters are weak to-- doubly so in Nocturne, Digital Devil Saga, and Persona 3 or 4, which use the "Press Turn" and "One More" systems respectively that allows for more turns by exploiting weaknesses. This works for and against you. Funnily enough, there aren't any actual demonic spiders.
 * In almost any game in the series, Rangda. She's pretty much the only random encounter that reflects physical attacks and only has one elemental weakness.
 * Shin Megami Tensei Nocturne gives us Zhen, who appears very early in the game, but it knows Poison Needle and Wing Buffet, both of which can be devastating this early on. The latter is made worse if you have a demon with a weakness to Force. Plus the only way to get one is through fusion, which you can only do if you're lucky enough to get to Shibuya (as they outright refuse to join you).
 * The trick to getting the jump on the Zhen is to recruit a Hua Po in the Medical Centre (usually in the basement area) that knows Agi, as it's Zhen's weakness.
 * All four enemies found the in the Second Kalpa's cursed hallway. Tao Tie has a cheap insta-kill that almost never misses. Abaddon has a ton of HP and is heavily resistant to all types of magic. Nyx has powerful Ice spells as well as a cheap combo of moves that puts your party to sleep, and then kills everybody that's asleep. Flauros can drastically reduce your attack and then smack you around with moves like Deathbound and Iron Claw, both of which hurt like hell. Yeah, good luck fighting these assholes, especially with your HP continually draining.
 * Persona 3, already a difficult game, had the difficulty ramped up to 12 in the re-release, Persona 3: FES. FES added a Hard Mode to the original game, which turns every single monster in the game into a Demonic Spider, and every boss into That One Boss. Amongst the changes—Your chance to run is lowered to single digits; enemies spells do over double damage; Enemy instant kill spells are MUCH more effective; and the Persona Compendium, which in Normal mode allows you to recreate past Personae for a pittance, has it's prices upped by 400 PERCENT. The difficulty isn't insurmountable, but does require very careful, intelligent play, and many, many savegames. FES even adds an expansion that ups the difficulty even further, removing your ability to resummon past Personae. There's one bright spot though; if you sneak up on a Shadow, your surprise round grants you auto-success on escaping in case you run across something that would destroy you several times over. It's small comfort, but there you go.
 * A more specific example: the Void Giants in Monad. Physical attacks heal them. Extremely high magic defense. Repel Light and Dark (as in, they bounce them back to you.) Armed with the highest-level of aforementioned Light and Dark spells (single-target and group versions!) as well as Myriad Arrows and Deathbound, which are very high-level multi-hit, all-party Pierce and Slash attacks, respectively. And they come in groups of two at least. Even if you sneak up on them, if you see two (or more) get consecutive turns then you might as well reset the game (or fuse a Persona that Nulls/Repels/Absorbs Pierce, Slash, Light, and Dark, and just say goodbye to the rest of the party.)
 * Before them, you get to do battle with the Creation Relics on floors 65-88. Their only weakness is Darkness—but all this means is Mudo is marginally more effective, and by this point you probably gave up on it working and don't have it on any Personae. They know Magarula, which they love to use in a row; two in a row will kill most of your party. And to top it off, if you can't kill them down to one in a single round (and they do love to come in threes), they know Diarama, which will undo all your hard work. Bonus points: they're the Subjugation Request for that level—you have to hunt them down. The really weird part is that otherwise, 65-88 is one of the easiest stretches of Tartarus. They reappear in part 2 of Malebolge, the first level of The Answer. And they're every bit as annoying, if not more so. The Relics now have more HP, know Twin Shot (a powerful Strike attack that hits twice), and on top of their original resistances, they now bounce back Strike and block fire attacks.
 * Any Jotun-type enemy is bound to become this. Each of them are resilient enough to qualify for Boss in Mook Clothing status, even if you exploit their weaknesses, and they hit REALLY hard. Appropriately enough, when you finally encounter one as a boss, it absorbs everything but Pierce attacks.
 * Many of the Crimson Shadows, both in The Journey and The Answer. The Avenger Knight in The Answer is one such example. He shows up in Cocytus - the second dungeon in the game - and can very easily rip you a new one if you're caught off-guard, and/or thought he would be easy like he was in The Journey or Persona 4, in which case you'd be dead wrong. He has no weakness you can exploit, quadruple-digit HP, blocks both types of instant-death spells, reflects Pierce (Aegis' attack type), and has the very nasty combination of Elec Break (to nullify a character's resistance to electric attacks) and Mazionga (second-tier electric spell that hits the whole party).
 * The Berserk Turrets, also in The Answer, are truly vicious. You know it's going to be bad when Fuuka pleads you to run away from them. They always show up in groups of five, have really high defense against everything, including their weakness (electricity), and they don't die from a single All-Out Attack. And once their turns start rolling around, the Turrets fall into a pattern; hit someone with Agidyne, then sweep the party with Heat Wave. The only spot of hope there is shows up when the AI Roulette spins in your favor and the Turrets waste their turns hitting someone that's immune to fire. And they're Crimson, which means they're rare.
 * Strange Journey does away with extra turns--instead, exploiting enemy weaknesses will cause same-alignment demons (and you, if you're of the same alignment) to perform a "Demon Co-Op" attack for extra damage. Thankfully, enemies CANNOT do this. However, you still need to be on the lookout for enemies with spells that have "Mudo" in the name, as well as enemies with stoning attacks (an instant Game Over if it hits you) or attacks that cause the dreaded "Bomb" status, which turns a party member into a bomb that explodes on hit.
 * King Frost will, if not killed quickly, heal himself back to full health over and over again and spam Mabufudyne and Explosive Fist between heals. And if he's with other mooks when he casts his healing spell, those mooks are also completely healed. Makes sense that he shows up in Eridanus.
 * Pisaca just loves to cast the Bomb status on your party, and unless you have Dis-Bombs, they will deal tremendous damage to your party hitting whoever they bombed. Pray that it wasn't the main character.
 * Encountering Takeminakata when you first get the Enemy Search is a classic newbie trap. He has a good amount of HP for when you fight him, and high defenses to match. Additionally, he knows Zan-Ei, which is really strong and more or less becomes a One-Hit Kill if he's encountered under a new moon. To add insult to injury, he doesn't give out experience when you beat him; he does, however, give you a Forma that can be pawned off for 3,000 Macca.
 * The cake of Strange Journey's Demonic Spiders is taken by Futotama. It is a dozen levels ahead of the other enemies in the zones you can find it in, has no weaknesses, is immune to istant death, hits(hard) all of your party at once with normal attacks, has the ever-annoying Macca Beam and Strange Beam magic that will rob you of money and MP, can use Turn Tables to reverse any debuff you inflict it, and once you whittle its health down enough it will heal itself fully with Diarama.Luckily, it only appears if you use the Demon Search function, but if you factor in that you can't recognize it until you beat one...
 * Persona 4 has the Wondrous Magus. It shows up fairly often at the higher levels of the bathhouse dungeon and likes to spam Zionga, Mazio and Maragi which at least two members of your party are weak against. It also doesn't have any weaknesses, take a while to kill, rarely shows up in parties of less than three and you can't even switch out for party members that are stronger against them until later.
 * From the same game, Marukyu Striptease has a random encounter that is a lot more common than it should be; four Idle Basalts and a Persistent Fuzz. The Fuzz can and will bounce back any spell used on it, leaving you with physical attacks to take it down. And even though it has no spells of its own, its physical attack does tremendous damage. And the Basalts have no spells either, but their attacks do even more damage than the Fuzz's. They're weak to ice, but good luck keeping them down with it. If you try physical attacks on it, you'll find that they resist it 20-fold. Fortunately, these two only show up on two floors of the dungeon.
 * Any random encounter with the word "Basalt" in its name is going to be a Demonic Spider. They greatly resist (and later outright ignore) physical attacks, have unpredictable weaknesses, and while they don't have many skills, their regular attack hits like a ton of rocks. Oh, and there's one type of them that resists Almighty. You will, more often than not, drain half your collective SP getting everyone's health back up after fighting a group of Basalts-- assuming, of course, you survive the encounter in the first place.
 * Remember the World Balance? You know, that boss from Persona 3 that knows every -dyne spell and responds to Magic Mirrors with Megidolaon? Yeah, the goddamned thing shows up as a random encounter in The Answer, with all its moves as a boss and quadruple-digit HP. And it isn't even Crimson, which means it's more common than not!

Wizardry

 * In Wizardry 8 the general power of Standard Status Effects means that fighting almost anything that can inflict an ailment can turn into an exercise in frustration, especially if the monster is particularly fast. This tends to include Rynjin (insanity, turncoat), nightmares (fear, insanity, turncoat, blindness), most plants (blindness, sleep, poison), and undead (insanity, sleep, paralyzation, fear). Late in the game, enemy spellcasters like Rapax Templars can even use the same buffing spells as the party (with Missile Shield being far and away the most annoying, as it negates a large portion of ranged combat and causes one to waste precious ammo if one isn't careful).
 * And yes, the game does have bats. They're annoying because they're really fast, meaning unless you freeze, sleep, or drive the lot of them insane they will invariably surround your party. At low levels, this means taking a lot of damage. At high levels, they can even cause HP drain, which is harder to cure than death.
 * One of the nastier examples are the Pixies in the Trynnie trees. Their powerful magical debuffs can render most of your party impotent inside the first combat round, their fast reaction time means they'll almost always cast first, and there's something particularly humiliating about finding yourself constantly running away from roving gangs of tiny naked girls with wings.
 * On the other hand, that's really all they have. They also possess pitifully low HP, and if they cast anything but Blinding Flash or the like, a single application of an area-damage spell will typically kill them all in a single shot.
 * Wizardry VI: Bane of the Cosmic Forge and Wizardry VII: Crusaders of the Dark Savant had more than their share. What could make them truly nasty is that unless the player is very experienced at the game (and knows when what monsters start appearing, and in what numbers), the Demonic Spiders are indistinguishable from the normal mooks without a high mythology skill on one of the characters. Examples:
 * Qua'Tari look like Ban'Tari at first (and Ban'Tari aren't slouches), but it's when you realize that Blinding Flash isn't working, and that they're hitting HARD, that you realize these aren't your normal two-headed lions. Veterans know to beware when the kitties show up near Ukpyr.
 * Lizards in Wiz7 in general are one of the tougher enemy groups, but Komodo Dragons are truly dangerous. Resistant to most magic, lots of armor, hard-hitting, acid breath that hits multiple characters, and a chance to instant-kill characters with physical attacks...
 * Helazoids could also be frustrating at lower levels-fairly fast, resistant to magic, hit hard, and their laser cannons can hit back-rank characters. All but the weakest variety have a chance to instant-kill as well.
 * The tougher Rattkin qualify, too. Rattkin as a whole tend to be Glass Cannons, but the nastier ones really emphasize the "Cannon", adding in poison, instant death, and occasionally stoning as potential side-effects.
 * Savant Controllers and Kui Sa'Ka. Not very fast, but resistant to magic (noticing a trend?), good armor, lots of hit points, and the truly annoying psionic spells that like to make party members go insane.
 * And God help you if you run into Conqueladas...

Other Games
"NPC: If you're all alone in the woods, and you see a troll coming, you run. Problem solved. Next question?"
 * Maple Story has an enemy in one area called the Stirge. It is a bat-like creature, which flies just above the hit area of most player's weapons. Combine this with a fairly high attack power, and the required quest that Dual Blades have to kill these things for, and you've got some serious Fake Difficulty.
 * Okage Shadow King was full of these. Foes generally either packed nasty status effects, could deal enough damage to kill you in a few hits, or had more HP than a freaking tank. Squads varied, and often had a combination of these, aided by legions of weaklings. This actually kept the game interesting though, as strategy was required for just about every encounter, but you could avoid fights to balance things out.
 * Any enemy in Secret of Mana that can summon more enemies, and slimes in particular. Fortunately, they are limited to having three monsters on the screen, but this is small comfort when the last one standing keeps making two clones before you have the chance to finish it off! Furthermore, the red slimes would set you on fire if you got too close while the blue slimes would turn you into a snowman!
 * Another annoying enemy type were Tomato Men and other enemies that could not be harmed by regular attacks (unless you got a critical hit). This forced you to either charge up your weapon (a slow and dangerous process when other mooks are beating on you), use magic (even though your mana pool is very limited early in the game), or run like a chicken. And yes, some types of slimes fell into this monster category.
 * Probably the worst offender was the Shape Shifter. It'd spawn a random enemy from a permanent set. One of the enemies it spawns? Eggplant Man. When you encounter a Shape Shifter for the first time, Eggplant Men is an enemy encountered at least two dungeons ahead. And to rub salt in the wound, Eggplant Men spawn Needlelions, which are guaranteed to kill a character at the point Shape Shifters are first encountered. And to rub lemon juice in that would, Shape Shifters are one of the hardest enemies to kill thanks to absurdly high defenses. You're better off running like hell.
 * Nearly any monster can become this, depending on circumstances, when night falls in Mana Khemia: Alchemists of Al-Revis. Ones that are already nasty can get boosted to the point where they become a Boss in Mook Clothing—without the usual rewards and fanfare the game attaches to such.
 * One in particular is the side job where you have to fight 3 Kyuubis in the Japanese PSP version; item lock, no HP/SP healing and fast initiative will ensure you will lose. HARD.
 * In Tales of Phantasia's ice dungeon, there are enemies called "Ekim." One Ekim in a group of enemies is nothing to worry about. However, when they appear in pairs, they embody this trope. The first one will prevent you from reaching its partner, who will invariably cast the devastating spell Judgment. While your party recoils from the blow, both Ekim will begin to cast this spell and proceed to spam it until your helpless party is destroyed. To make things more irritating, it is possible to go for more than an hour without reaching a save point.
 * Speaking of Tales, in Tales of Innocence's secret dungeon, there is an enemy that resembles a bee. These generally come in groups, are incredibly fast, have great attack power and attack several times. By the way, the dungeon has 100 floors and you can only save by getting out of it.
 * Phantasy Star Universe has dozens of Demonic Spiders. A couple of examples:
 * The Svaltus is large humanoid thing about 10 feet tall and with a huge sword on its arm. It has a linear, long-range shockwave which can randomly stun you if it inflicts damage—which, given the attack power of the Svaltus, is pretty much every time it hits. Stun status renders you unable to move, heal, or in fact do anything but stand there and let it and its pals beat on you without fear of reprisal. They take reduced damage from bullet attacks and have a shield which they will use liberally and without restriction which eliminates bullet damage while active, making guns useless; And if you try to melee them, they will use a spin attack which will inflict the Zalure defence-down status effect on you and send you flying, unless you happen to block it. (don't count on that) Oh, and did I mention they like to spawn in packs?
 * Zamvapas and Galvapas are large quadrupedal creatures with an annoying tendency to charge, which they will do so for long distances. Against low-levelled players the charge does hefty damage, but even if you're level Awesome and evade every time, you still have to go chasing after them, at which point they will inevitably charge AGAIN, and AGAIN, and AGAIN. Repeat ad nauseam. In addition, they have obscenely high defence when hit anywhere but their head, making the risky head-on assault the only way for those without TECHNICs to do appreciable damage. Which inevitably leads to the irritating charge-chase-charge malarkey, over and over.
 * Grass Assassins are another instance of "large goddamned bats," unlike the Grass Assassins which appeared in Phantasy Star Online. They thoroughly enjoy charging, sending your character flying into the nearest wall every time it hits, even if you only take a single point of damage. They also possess a spit-take attack, which almost always inflicts the stun status effect should it do damage. Add to this the fact that Grass Assassins always seem to show up in packs, and will often take it in turns to use the spit-take, and the Grass Assassin is an exercise in controller-snapping frustration.
 * Ubakrada are another example from this game. All of their attacks, save their elemental projectile attack, comes with very little warning, and half have the ability to send a player flying should it cause any damage at all. These attacks include a charge, and a quick sweep that also serves to turn the creature about 90 degrees, making it almost impossible to get behind the thing, which is a useless tactic anyway, since it will just perform a back-kick and knock you down. And those elemental projectile attacks come in the ice and light varieties (depending on the element of the creature), which will freeze you solid or put you to sleep, respectively.
 * A few enemies from The World Ends With You fall under this. The blue noise and elephants can be easily avoided, fortunately.
 * Any Taboo Noise. They're stronger than the Noise they're based off of (except perhaps the drakes), have ridiculous amounts of damage reduction unless you have the light puck, requiring you to really move the puck efficiently if you want to hurt them at all, and actively seek you out during a scan. On top of all that is the fact that running away is disabled during Taboo fights, meaning that you can't even run from them.
 * Minks: the non-Taboo form of this enemy chain is actually deadlier than its Taboo form. Why? It can use a breath weapon that deals absolutely horrifying damage (the Taboo version doesn't). If it uses it on the top screen, it is virtually an instant kill-it is continuous, essentially impossible to block in its entirety, and can't be avoided on the two-dimensional battlefield of the top screen (unless the player's partner is Joshua and can levitate). The player's only real chance is to go hyper-aggressive and hope to kill it before it does the breath attack.
 * The Taboo Drake is annoying as hell to kill, too—especially if you've been dropping your level for the Ultimate drops. Top screen faces spears from above, bottom gets the standard Taboo treatment. It isn't as hard to kill in the New Game+ because you can use Joshua, who levitates, thus avoiding most of the drake's attacks.
 * Neverwinter Nights, another DnD game, has a bodak in the Jhaereg castle. This bastard has a gaze attack that kills instantly if you fail a Fort save. Did we mention that wizards, sorcerers, and rogues all have crappy Fort saves?
 * Not to mention an earlier and literal instance of the trope, the bloated dire spider. This thing is level 10, whereas most players will be level 7 at the most when they encounter it, and not only can it knock you down, rendering you defenseless for a painfully long amount of time, it has slow-acting strength draining venom, meaning unless you can cure yourself somehow, your damage output will slowly be reduced to nothing and you'll become so encumbered you won't even be able to walk at a normal speed.
 * The expansions give us the secret room in the final dungeon of the interlude of Shadows of Undrentide that contains eight Basilisks (eight save-or-die effects per round...), the Bonus Dungeon under the Beholder lair in Hordes of the Underdark (all magic items are rendered nonmagical for most of that dungeon (which nerfs non-casters) and magic does not function (which nerfs spellcasters), and while its occupants' aren't much of a threat normally once you've lost all magic their Strength-drain effects begin to add up), and the Beholders themselves (with infinite-use petrification effects, no less).
 * Another vanilla NWN example: high-level duergar in the fire giant dungeon. If you had enough experience, groups of deep dwarves would frequently turn up with a mage rocking Phantasmal Killer, a spell which instantly obliterates you if you fail both a will and a fort save, and still hurts if you pass the fort.
 * Eye of the Beholder
 * In the first game, applied literally with the Giant Spiders.
 * In both games, thri-kreen (mantis warriors). They're incredibly fast, tough, and have a paralysing bite that makes it pretty sure one of your meat shields will be incapacitated before having even a chance to strike. So much that fighting them one-by-one is actually a less favorable option than facing a swarm of them -- then at least you can spam offensive spells more efficiently.
 * Star Ocean: Till the End of Time has a few. Proclaimers are angelic monsters that use, every few seconds, a high damage attack that is unblockable and has a longer range than Maria's pistol in all directions, not to mention being encountered throughout the game starting about halfway until the predictable controller/screen interfacing inevitably ensues. Wisps have an even stronger all round attack, and to make matters worse there's a room in the Bonus Dungeon where the player must defeat ten groups of them followed by a (thankfully easy) boss without saving. Decahedrons and crystal statues are so fast that landing more than one blow is nearly impossible, never flinch and, needless to say, have lethal attacks. Most guides also mention Convictors (proclaimers' big brothers) in this context.
 * Much, much worse are the Sooties in the bonus dungeon, Sphere 211. Not only do they hit for insane amounts of damage and are much, much faster than you... they're about six inches high (meaning many attacks simply can't hit them) and are essentially mobile dust clouds with cute little caps and glasses on. Not just frustrating, but embarrassing at the same time.
 * Did you all forget the part of Sphere 211 you're supposed to go through during the story? The soldiers there are just a minor nuisance, but all the robots? They rip you to shreds. Especially the spider-like ones with the missile spam that juggles you in midair, which happens to be a strong attack so it breaks your AAA, and their AAA happens to be the first one in the game to heal the user, meaning if you screw up a weak attack they're getting healed. Oh, and while one by itself can be manageable, they often come in twos so that they can take turns juggling you. Have fun
 * Star Ocean the Second Story has Salamanders and their palette swaps, which have a breath attack that, in theory, hits the character(s) in its path 2-3 times and pushes them away. However, very often, obstacles or the arena boundary prevent the characters from being pushed, and the attack hits over a dozen times for an instant kill. As if that weren't enough, it can cause some of the worst Standard Status Effects depending on which palette swap it is.
 * The SFC version of Star Ocean featured enemies in the final dungeon that could turn you to petrify by contact. In a game where there's no guaranteed way to guard against petrification and if everyone's petrified, it's game over. They went the extra mile by designing random battles where your party starts out sandwiched between two of these enemies, guaranteeing that at least two of your party members are going to be petrified right at the start of battle.
 * The standard enemies in the Kingdom Hearts series of games are generally pretty manageable. Not so the special enemies in the Final Mixes. Of these, the worst would have to be the Stealth Soldier in Kingdom Hearts Final Mix. Let me elaborate on why, exactly, this Heartless sucks so bad for the non-import-gamers in the audience: First of all, he's invisible. Completely. There might be a faint shimmer, but because he's tiny, it's usually impossible to pick up on. Secondly, he's fast. Easily much faster than Sora is. Not even Stop will slow him down for longer than a half-second. Thirdly, and as expected for a Demonic Spider, he hits like a Mack truck. Three consecutive hits without a chance to heal will quickly put Sora at critical health if not kill him outright, and given Stealth Soldier's speed and invisibility, said three hits come quickly and are reeeeeally hard to avoid. For another, your one chance of keeping tabs on him--the game's target lock-on--he can throw off any damn time he pleases. The Stealth Soldier appears in the Hollow Bastion area, which, for those of you not in the know, is the game's penultimate level and stuffed with the hardest Mooks in the game. Naturally, the Stealth Soldier always appears in a crowd of these, so you can be beat up by Defenders and Wizards while desperately trying to find and exterminate (with EXTREME prejudice) the Stealth Soldier. Plus, the Hollow Bastion level is notorious for its many difficult boss fights, meaning that you will spend a lot of time levelgrinding there, meaning your chances of running into the foul beastie as much as possible are maximized. As if that wasn't enough, Stealth Soldier's appearances are randomized, so unless you have eagle eyes, you won't even know he's there until he starts killing you. The icing on the cake? If you don't kill him quick enough, he disappears, sparing you from more humiliation, maybe, but also keeping you from drops, EXP, and the satisfaction of killing the little bastard. Oh, and his drops? Have a chance of including a rare and exclusive synth item, which you will need to unlock the Infinity+1 Sword. Happy hunting.
 * Kingdom Hearts II appropriately brings in two more: the Hot Rod Heartless found in Timeless River which, once reaching a certain amount of health, will start spamming an attack in which they become invincible and charge at Sora thrice. They do become trivial once you get Magnet though. The other, the Devastator from Space Paranoids, has high health, attack and defense and can 'switch forms' while you're in the middle of comboing it without warning, hitting you several times for lightning damage if you're up close. They usually come in groups of two with several other enemies. Worst of all, they are immune to Magnet.
 * Dancers. They have a move where they turn invincible, slide across the floor towards you at high speed, grab you, swing you around, and throw you. This move is completely unblockable and very difficult to dodge. The Titan Cup, especially the Titan Paradox Cup is made a nightmare because of the battle where you have to face three Dancers.
 * Coded brought us a more literal example in the form of block spider heartless, specifically the ones you encounter in Data Riku's body. You can take out several swarms of these things and still never run their spawning point dry. The worst part? they have a chance of changing into different kinds of blocks, which include metal blocks (this flavor can turn itself invulnerable by retracting its legs), bounce blocks (send you flying back with each landing hit), and danger blocks (hurts you with every hit you land on it).
 * The Cavern of Remembrance in Kingdom Hearts II Final Mix + is filled with these. Every single enemy found there qualifies (well, except for maybe Perplexes, with are literal Goddamned Bats). Two of the enemies found are Recklesses and Mad Bumpers, which are stronger Palette Swaps of enemies (Terminator and Hot Rod, respectively) that are Demonic Spiders to begin with. Finally, the last area features hordes of stronger-than-normal Nobodies. The Berserkers, Dancers and Sorcerers will make you willing to snap your controller in half.
 * Might and Magic VII plays this trope to an extreme. First, any particular breed of monster comes in three different strengths (e.g. Goblin/Hobgoblin/Goblin Lord), and anywhere a particular breed appears, the higher strength monsters have a chance of occuring. The strongest of the breed is usually roughly 3 times stronger than the weakest, which can result in an inappropriately powerful monster appearing in a lower-level area. And aside from that, many of the stronger monsters have hit effects that can include such things as "Instantly Drain MP to 0" and "Instant Death." Yes, there are monsters in MM 7 that can automatically kill you just by hitting you. If you play MM 7, you will come to loathe Minotaur Lords, Ancient Wyverns, Devil Captains, and Elder Vampires.
 * And then there's the spell "Dragon Breath." It's like a fireball: it explodes on contact and hurts everyone. It will probably kill your wizard and healer immediately, and even your meatshield will go down after 2 or 3. Oh, and the creatures that can use it are immune to it, so they can cast it while standing right in front of you and suffer no ill effects. And monsters in MM 7 don't have MP, they just use whatever magic spells they're programmed to use randomly. A spell doesn't count as a Demonic Spider, but any monster that can use it (Queen of the Dead, Lich King) sure does qualify.
 * Adventure Quest is usually a fun game, but Sneaks have been known to send unsuspecting players into apoplectic fits. They're nearly impossible to hit except with ranged attacks, most of which are near-useless in any other context. But even they have nothing on Xyfrags, which only take 30% damage and have thousands of HP. The slimy bastards are so much of a problem that there is a weapon with a trigger effect specifically meant to kill Xyfrag. It doesn't help that once you get to the level you will begin to see Xyfrag, the weapon becomes utterly useless. The entire fandom cheered in unison when they were made into a rare encounter; before that, they were so common it was nearly impossible for a high-level player to go through a quest with more than one random enemy without running into one of the damn things.
 * This is an example of Revive Kills Zombie. Element X weapons/spells are available, although most of them cost HP.
 * Also, Am-Bushes, a Lightning Bruiser with defenses even higher than a Sneak's, and without the vulnerability to ranged damage or any sort of elemental weakness. They always go first and hit so hard it isn't even funny, especially if you're using a Glass Cannon character build. Oh, and they're everywhere- they're extremely common both in random encounters and set battles in quests, so good luck avoiding them.
 * Anything that can drain your stats. Particularly since nearly all the monsters are level-scaled, so Level Grinding makes things worse... yet most of the equipment is so expensive you need to grind if want to be able to afford it.
 * You really, really aren't supposed to fight the Shadowlords in Ultima V. Upon entering combat, they teleport you to their dimension; which boxes each character in a chamber alone. They can walk through the walls of the different chambers, can move multiple times per hit, poison your characters, charm them, they hit like a mofo. And then, even if you kill one in battle, it just reforms elsewhere.
 * On TOP of that, if you have the Sceptre of Lord British -- one of the vital items needed to win the game, and  -- they automatically reclaim it. And you have to trek all the way back to   to recover it again. This can happen several times.
 * In Ultima VIII: Pagan, there are kith, giant bloodthirsty spidery-things that you encounter randomly in the wild, and can kill you in one hit. And if you run into one, and it actively pursues you, RUN.
 * Vampire: The Masquerade Redemption: the Nosferatu and the Tremere. The Nosferatu turn invisible at will. Attacking you doesn't break said invisibility. Unless you've bought yourself some form of heightened senses power (doubtful, since they are otherwise useless), you're hosed. And then there's the scumsucking Tremere, who are vampires AND mages. They come in big packs, and spam such lovely spells as Mind Control, Lightning Strike (aggravated damage, hits your entire party), Fireball (same, plus lasting fire damage), and the ever lovely Freeze, which does Exactly What It Says on the Tin—and high damage, of course. Did I mention that aggravated damage inherently has high chances to make your party members go berserk and start using their powers at random or, even more fun, biting the neck of the nearest person, which makes her helpless as long as the biter is drinking? That nearest person is you. Always.
 * Arcanum: Of Steamworks and Magic Obscura has Ore Golems. Attacking them with a weapon damages the weapon. Attacking them with your hands damages YOU. They can kill a character in two hits, can hurl stone-spells which take off two-thirds of your health, are GREATLY resistant to damage and are all but immune to firearms. What makes it worse? Most new players will encounter them at a fairly low level if they follow the main plot. You have two choices in dealing with them: spam Harm, or an Elephant Gun. The Elephant Gun is a rare high level tech rifle that you probably won't see until mid-to-late game while Harm is a first level dark necromancy spell, and the location that throws Ore Golems at you throws tons of them at you. Hope you rolled a mage. Or have electrical weapons, if you follow on that tech tree.
 * Same goes for the Mechanical Arachnids and Automaton enemies. Bonus points for the Mechanical Arachnids being actual spiders.
 * Also, various fire elemental/lava golem monsters. Most of the problems posed by the ore golem, plus they have fire damage that rips apart your armor.
 * Elephant Demons in Jade Empire can cause devastating shockwaves when they pound the earth, making it hard to get close to them (and demons are immune to magic). The Horse Demons also have the ability to damage your character with a fire shield when you hit them, and have a fair assortment of melee and ranged attacks.
 * The RPG Astonishia Story has a cave/secret tunnel that has the highest encounter rate in the entire game, and the enemies are ghosts, skeletons, and zombie-werewolf things that are nearly impossible to hit. No matter what you do, you miss more than half the time, and then they use a spell that can take out half your party in one shot. (The other half just barely survives.) Better yet, sometimes you can't run away until the third or fourth round. Unless you have smoke bombs.
 * Blue Dragon has the Steel-Eating Tigers. Vicious monsters that can two-shot your toughest characters (and of course, one-shot the weaker ones)? Nasty, but manageable. Until you realize that they're so damn fast that they can easily move twice in a row if they want. Be ready to revive more than a few characters when you get drawn into an automatic encounter with FOUR of them.
 * In Knights of the Old Republic, rakghouls, when you first meet them at a low-level. They're fast, numerous, generally don't miss, are the first time you encounter poisoning, and they are creepy. In fact, most of Taris will turn relatively simplistic enemies later on into demonic spiders. The torture droids in Davik's mansion, for example, would be laughably easy... if your only Jedi actually had the chops to use Stun Droid without them saving against it half the time. Droids in general also get ridiculous special weapons that can do a lot of damage to even the most well-armored player.
 * The will o' the wisps in The Elder Scrolls IV: Oblivion. They're immune to normal weapons, are practically invisible when moving, and their preferred method of attacking is to absorb your health and magicka, which simultaneously damages you, prevents you from casting any healing spells, and undoes any damage you may have done to it. However, Will o' Wisps, like other specters, are not immune to the almighty power of your fists if you're a journeyman.
 * Trolls, too. They're fairly common in certain parts of the overworld, they're fast enough to keep up with you on horseback, they're persistent, they have a ton of health, and they do a ton of damage. Their Demonic Spider tendencies are even lampshaded by an NPC:


 * The Clannfear might also be considered under this trope--you lose health every time you hit one, so fighting more than two or three is suicide, and either way will always result in a fortune's worth of potions being consumed. Unless you toast them with magic.
 * The atronachs also deal damage to you whenever you want to get up close and personal. Especially frost and storm atronachs are a nightmare to deal with for melee characters, as they also have ridiculously high health.
 * There are literal Demonic Spiders in the the Spider Daedra. They are tough, deal good shock damage, has an ability damaging spit, and to top it off summon little Spider Daedras that do pretty much the same thing, only they can paralyze you. Did I mention that they can heal themselves?
 * You know what the real Demonic Spiders of the game are? Bears. They have ridiculous health, are relatively fast runners, stagger you with most of their attacks, which happen to do a LOT of damage which is not reduced much by blocking, and don't recoil from hitting your shield. They attack at a much higher rate than other enemies of comparable strength, and they attack with a lunge, so good luck getting out of its attack range.
 * Spriggans are incredibly tough by themselves, they can also regenerate their health three times before dying. And guess what? They summon bears.
 * The Scamps are really fucking annoying. Their attacks can be extremely unpredictable at close range, their fireball attacks have the uncanny ability to predict where you're going to be, and they can take a ton of hits for a weaker character to bring them down.
 * Above all: if you level up too much in the vanilla game every single monster becomes a demonic spider due to the fact things level up along with you. At least if you have one of the many gamebreaking items (reflect damage, resist/absorb/reflect magic, chameleon), you can ignore every enemy after level 30. Good luck reaching level 30 though.
 * Along with the usual Trolls and Spriggans and Bears (Oh my!), Skyrim has Sabre Cats. They're stealthy predators that seamlessly blend in with their surroundings and stalk you without making a sound. If you aren't observant to the point of paranoia, you won't see them coming until they've lunged at you and clawed you to death before you can even fight back.
 * Giants, whose attacks will usually send you flying to the moon in one hit. Thankfully they're a passive race that won't attack you unless you pick a fight with them, but some scenarios (radiant monster-killing quests, ) make conflict with them unaoidable.
 * Also from Skyrim are the Chaurus. They're durable, spit poison at you, and will likely murder you in a few hits in melee unless you have very heavy armour on. Oh, and certain Falmer caves are flooded with them.
 * The Draugr Deathlords you meet at higher levels can be really unpleasant. They are built like tanks, hit almost as hard, and they have Dragon Shouts. Which they use to disarm you or send you flying while their minions (they rarely show up alone) chop you to bits. Then when you're at a high enough level, they're the minions to the even stronger Draugr Death Overlords (or in a few rare cases, Dragon Priests) and aren't a single bit weaker.
 * Anything with the Disarm shout counts. Nothing like getting your unique, fully upgraded, ultra-powerful weapon blasted out of your hands and into some corner where you can't ever find it again. They can't do anything with bound weapons or magic, though.
 * In later stages of the game, the dragons themselves. They often come out of nowhere wherever there is open sky, usually when you're trying to do something else, and normally take a while to finally take down. The first few dragon fights are epic, but then they never stop coming. And once you're leveled enough to take on a dragon with ease, the Elder and Ancient Dragons start appearing...
 * The random trainers in Dragon Warrior Monsters have quite a few monsters that can be bothersome even considering they are supposed to match your levels, but Fang Slimes in the level sum 99-118 group take the cake. On top of being ridiculously fast, they come armed with War Cry, a skill that causes all enemy monsters to lose their next turn. It is naturally possible to have monsters that can resist this and have a chance of not suffering from this, but the game doesn't tell you which ones or how well. This is made particularly bad by the fact that various other monsters in the group like to have powerful hit-all attacks, so you're having to heal every other round except, oh right, YOU CAN'T. And the same level sum group has Bomb Crags that know Paralysis Air, which short of having monsters immune to it is capable of paralyzing all of your monsters and causing you an instant defeat. And unfortunately, they have high HP and defense so you can't kill them quickly either.
 * In Cross Edge, you can end up meeting Cilone, a level 190(!) enemy with insane physical dodge and crazy magic resistance. Normally, this would be a Boss in Mook Clothing; however, there's a DLC dungeon where Cilone are regular encounters. And if you thought Lujit's A-Fear was bad, Cilone's attack of choice is Ragnarok, which it will spam until it ends in a Total Party Kill.
 * What makes Cilone even worse is that, like Lujit and its ilk before it, it has both Parry and Pefect Barrier, negating physical and magical attacks at 25% HP, meaning EX skills are the only way to go. And for something even worse than that, they are regular encounters in the third area of the fifth world, and are buffed to level 750(!!!), meaning that unless you've some godly speed, you can't run away. Better hope you saved or you've got good defenses.
 * In Realmz: City of Bywater, the demonic spiders are actually demonic spiders. The random encounters in the appropriately named Spider Tower paralyze and poison when they attack, have high hit points and tend to appear in random encounters with you already forced against a wall, surrounded, in a small room. Just when you thought things couldn't get any worse, in the final battle against – yes – more demonic spiders (the writers clearly realised they didn't need a boss), a second legion of reinforcements swarm in while you're finishing with the first. (Or while the first are finishing with you.)
 * Dragon Age has many enemies who can pin a character down and maul them until they die, with very few ways to stop this. The first time you encounter this is a boss, where an Ogre will pick up a random party member and punch them in the face until death. You can only stop this by stunning the creature somehow, and most of the creatures that have this ability are incredibly hard to stun.
 * The worst of these kind of enemies are, appropriately, giant spiders. Not only can they do the aforementioned pinning and mauling, they can also tangle party members in web and some have painful venom. Good luck if you're leading your party with a mage in the Deep Roads, because they can drop down from the ceiling, web your tank, then kill your mage without you being able to use any spells at all. And mages are VERY important in this game for large encounter survivability.
 * That Ogre boss also has a tendency to head straight for the player character, so if you're playing a mage (IE relative Easy mode), the fight serves as the first rage-quit-hard single fight in the game. Mages also get boned in their very first available side quest, where you are sent to go take out foes who use the aforementioned stun attack, at a level where you can die in a few seconds if things are going right. Appropriately enough, these foes are spiders.
 * At a high enough level enemy archers start using Scattershot, which stuns your entire party and is almost impossible to resist. It wouldn't be so bad by itself, but enemy archers usually come in groups that consist of more archers who also use Scattershot.
 * Enemy mages. At higher levels they spam chain lightning (high damage and mana/stamina drain against your entire party), Curse of Mortality (continuous damage and prevents healing), Crushing Prison (damage and lockdown), and Misdirection Hex (renders your physical attackers useless). They are rarely ever alone, and are often joined by the other Demonic Spiders mentioned earlier.
 * On the opposite end of the spectrum, there are dwarves. They are highly resistant to mana, making a mage's life hell. Guess what kind of enemies you have to face most often in Orzammar...
 * Dragon Age II has, perhaps to payback players who abused the insanely overpowered player mages in Dragon Age Origins, made enemy mages incredibly dangerous. They're invulnerable to damage except when casting spells, most of which they do without warning and can cause a Total Party Kill, and, unlike player mages, don't aggro every single enemy on the battlefield by casting a spell, don't get stunlocked in melee combat, and are decidedly not Squishy.
 * The Mimics in Mystic Ark. Despite that you only encounter them once throughout the entire game, they fit this bill quite well. They're notable for knowing the Blackout spell, which is a much improved version of the Kill spell and has an incredibly high success rate. They also tend to cast this spell the first chance they get, so be quick with the Deathguard spell or else...
 * Paper Mario 64:
 * The Crazee Dayzees of the Super Mario Bros.. series transformed from slow, weak minor enemies in their debut in Yoshi's Island to tough mofos who traveled in packs and inflicted the dangerous sleep condition at a very high rate in this series. Particularly bad in Paper Mario: The Thousand-Year Door, where the Dayzees almost always outnumber you and will frequently put both characters to sleep before you can finish them off, which pretty much guarantees a massive beating if not death.
 * Super Paper Mario may have it the worst--they're first found on a jump-centric That One Level!
 * There is also a Metal Slime version called Amayzee Dayzees, which not only behaves similar to one (high HP, huge reward for beating it, tendency to run the first chance it gets to), but also possess the strongest single attack in the game, at 20 damage. They can show up periodically in the second game's Pit of 100 Trials, which can turn a battle that's already tough into a stressful nightmare as you hope and pray that they'll just leave.
 * They'd get nerfed in The Thousand Year Door, but the Dark Koopas in the original Paper Mario are no joke. They're meaner, tougher, and sturdier than normal Koopas, but the thing that makes them such a threat is their Dizzy Shell attack. It comes out fast, and if you're unable to block it you'll be left with a helpless, dizzy Mario unable to defend himself while the Dark Koopa and his buddies take turns whaling on him. They aren't even rare or obscure enemies either: certain rooms of the Toad Town sewers are infested with them, including the path to Shiver City.
 * Don't think that Hammer Bros are going to lose their Demonic Spiders status because of the genre change: they're just as tough in the original Paper Mario as they are in the platformers. Their 12 HP is decently meaty by this game's standards, especially since their hammers can potentially shrink Mario and cut his attack power by half. Get their HP down past a certain threshold, and they panic to the point of throwing rapid flurries of hammers at you. And if you think they're already annoying by the standards of enemies during the endgame? You can fight one as early as Chapter 4 depending on the choices you make when Peach is being interrogated by Bowser and Kammy, serving as a fairly tough miniboss.
 * If you first fight them in their "proper" debut chapter, Bzzaps! are a joke because of their hilariously low HP. But if you find the hidden Bzzap! hive during Chapter 3, you'll learn exactly why they're lategame enemies under normal circumstances. In between their tremendous attack power of 6 and tendency to poison or shrink you, their meager 3 HP is the only saving grace you're afforded against these angry stinging Glass Cannons.
 * Paper Mario: The Thousand-Year Door:
 * The Spiked Parabuzzy in Chapter 6. Take Jr. Troopa's fourth form in the first game and multiply him by about 3. Per room. And you might not have the Spike Shield badge if you can't get past the retracting Spikes of Doom trap protecting it. To make things worse, the only partner to hit them without being damaged him/herself is Vivian, who can't damage them because of their immunity to fire! If you haven't equipped Hammer Throw, just run away. Or use Flurry's defense penetrating Lip Lock on them. Or use the second star special... hope you've been warming that audience up.
 * The Piranha plants in the Pit of 100 Trials don't seem impressive, but their attack of 9 adds up, especially since they often come in groups their having 15 HP makes it difficult to kill them all in one round, so most players will take a fair amount of damage fighting them.
 * Almost everything in the lower levels of the Pit of 100 Trials. The first ones you'll encounter are the Badge Bandits, whose attacks are hard to guard against and, as their name suggests, they can steal your badges. Later, you face Wizzerds, more powerful versions of the Dark Wizzerd enemy from the Palace of Shadow. It gets even worse near the bottom, with Spunia, the aforementioned Piranha Plants, Arantulas, and Dark Bristles, which are very difficult to hit without getting hurt and have a whopping 4 defense! On the lowest levels, you'd run into Amayzee Dayzees, Poison Puffs (with the ability to store up poison, surrounding them in a cloud of unapproachability and allowing them to do a breath attack for 10 damage and chance of poisoning), Swampires (with and the ability to drain your HP), Bob-ulks (which would charge up before unleashing a self-destruct attack so that they'd be up to 16 by the time they hit--including a defense boost almost immediately in the sequence.), and the absolute worst, Elite Wizzerds--12 HP, 7 attack (8 with beam), 5 defense, and the full complement of buffs. And for some reason, they tended to appear in groups of four or five. 5 Elite Mooks at once practically amounts to a boss battle.
 * The Met3EX, a souped-up version of the common Mettaur virus from Mega Man Battle Network 5. It's main problem is it's ability: the shockwaves it produces turn any panel poisonous. You have about 5 seconds before you can't stand anywhere without rapidly losing Hit Points. And with 300 HP itself, you probably don't have a chip that can insta-kill one. They show up again in the sixth game as RareMet2.
 * On the subject of Battle Network, the second and third games feature Scuttles, which are practically demonic armored elementally-aligned deathray-shooting robotic spider viruses. It's not until the third game that they start being a problem. The green ones sprout vines that move across the field and crush you For Massive Damage, requiring obscene amounts of Button Mashing to get out of, all the while holding you still so the others can murder you; the blue ones spit guard-breaking ice cubes that clog up the field FAST; the red ones shoot fire towers insanely easy to faceplant into dodging everything else; and the yellow ones call down lightning with completely unexpected timing, which are also easy to faceplant into if dodging too fast. Oh, and the white and black ones shoot DEATH RAYS OF DOOM. And they have stronger auras. The event battle required to obtain their Virus Chip to summon one, which many players newly visiting the Bonus Dungeon will accidentally run into, will kick your sorry ass back to the surface. Oh, and they become a random encounter in the final area of the Bonus Dungeon. IN GROUPS. Beware.
 * Bladias in the fifth game. They have the ability to erase panels you've Liberated and turn them back to Dark Panels, plus their Darkloid attack has a good range, and these don't involve actually fighting them. The first form of a Bladia has 200 HP, and that number keeps climbing throughout the game. They can block almost anything with their sword when they aren't attacking. The actual attack can crack an entire column of panels, leaving you with that much less room to move about. Let's not talk about how horrible this is when you're surrounded and at the mercy of other viruses... Players of Colonel are less screwed as Knightman's personal Chip breaks guards and does a nice amount of damage in the process.
 * The Ratty virus are mouses that shoot bombs that slide along the floor and try to turn towards you like Magnet Man's magnets. What's troublesome about those mice is that they become extremely fast when they're low on HP. Not only that, but they always avoid standing directly in front of Mega Man. You better delete them on a single hit or you'll suffer.
 * In Tales of Phantasia golems, especially on the higher difficulty levels. They take ungodly amounts of damage, hit quite hard, can knock Cless back and stun him with annoying regularity, and bunch the party up allowing their long reaching attacks to even hit the back row casters. To top it off they are usually acting as meat shields for enemy mages who will nuke you into oblivion. On hard mode, being surrounded on both sides by golems usually spells death unless you use tricks to escape, or go all out with abilities to kill one ASAP.
 * In Nolstagia for the DS, Sand Worms in the second dungeon will gang bang any player walking in. They come in groups of four and each are as strong as any other enemy in that dungeon, so without copious level grinding all you can do is run.
 * Orcs in the Gothic series. In most RPG settings, orcs are disposable fodder-type enemies. Even the lowliest orc scout in Gothic, on the other hand, is more than a match for your character for most of the game, and when you're finally tough enough to beat the scouts down, you start to run into elite warriors.
 * Most enemies that can inflict poison in Resonance of Fate. Most sources of damage to your characters deal Scratch damage, which can be healed fairly easily and only moderately messes up your day if a character takes all their HP worth of it. Poison ignores the protection that is normally offered by the hero gauge and go straight to dealing Direct damage every second or so. Direct damage is a true loss of HP, there's only one item in very limited supply that can heal you from it, and if any one character loses all their HP it's game over. The damage you take from poison isn't a big deal in itself, except that it will lock in any Scratch damage you've been taking as Direct damage as well - and the attacks that poison your characters tend to hit you for a pretty big chunk of that at the same time. You can heal from poison, but not before the first time it pings you and locks in all the Scratch damage, and the enemies will usually just do it again.
 * Any high-level mage in Oscuro's Oblivion Overhaul. Their AI has been enhanced from vanilla Oblivion, so they dodge your ranged attacks. They never seem to run out of magicka, so they can keep shooting very powerful spells at you forever. Spells fly much faster than in vanilla Oblivion, so they are harder for you to dodge (especially the shock spells), and every time they get low on health, they will regenerate a good chunk of it back. Even worse, due to the way OOO works, these ultra-mages con be encountered at any level, even level 1.
 * The Nocturne Equites in Sonic Chronicles will not only dodge almost every attack you throw at them, but counter it. That wouldn't be so bad, if they didn't do about 1/4 of your health with each hit, and heal every time too! This means attacking them will usually give them more health!
 * Every enemy in the NES game Dungeons & Dragons: Heroes of the Lance falls under this category, not only because they inflict great damage and slink away while you try to hit them, but because the god-awful control scheme makes hitting them even when you are standing in the right place nearly impossible.
 * The SNES game Soul Blazer has the demon fly. Seen in large numbers in the last stage, it is a small, fast, erratically-moving creature with surprisingly large amount of Hit Points, and on top of that, it is invulnerable part of the time.
 * In Hellgate:London, most players have developed a rather unhealthy dislike (read: primeval, seething hatred) for the enemies in the "Pain Leech" line, big tentacled floating heads. They seem harmless enough—damage capabilities only slightly above average, and really limited speed. Easy meat, right? Well, yeah, if you're fighting a single one. However, the danger of Leeches increases exponentially with numbers, since their lack of speed is handily supplied through their teleporting abilities, which means no matter how much you run, they're going to keep hitting you until you drop them. They also chew through shields like butter when there's more than about three of them, can cause the "phased" status (which causes you to sustain an extra 50% damage on every received hit and deal half damage) and have an uncanny ability to appear right in the middle of your escape route when you're running the hell away from a mass of missile-toting darkspawns or simply trying to find a moment of respite to recharge your skills. Taking all this into account, it's easy to see why the expression of most Hellgate players hardens when they hear the unmistakable moaning of the Leeches.
 * The "Bruiser" line consists of large, lumbering zombie cyborgs with maces for hands, which induce a stun effect. What makes them so broken? They're ranged and spawn in packs of 3 or more, which can leave even the toughest tank permastunned for the next ten minutes while they shoot you to death. Up close, they even have the ability to increase their defence and health regen, which just gives them even more time to set up a stun.
 * Then there's the "Blood Coil" line: annoying blind little reptilian beasts with suicide spikes, which induce poison or phase effects. As noted above, phasing increases damage taken and decreases damage dealt—which makes it harder to kill the next little beast that's kamikaze-ing you. Did we mention that they, like everything else, spawn in packs? And that later versions like Riftcoils can teleport and cloak?
 * And then there's the "Tortured Soul" line. Normally, they're blind demon shrimps that don't do anything unless you come within 20+ meters of them. They're easy pickings for ranged characters with sniper skills. Of course, when you do get close, their only attack is an unavoidable teleporting strike. Which phases. (See above.) Also, they don't target pets. And when you consider that out of the 6 classes in-game, 2 are melee and 2 are pet classes...
 * And the "Orbile" line, floating blobs with eyeballs. Mainly attack with lightning and self-destructing mini-Orbiles called Polyps. Defence in-game decreases with continuous attacks (claimed to make hordes of weak mobs more of a threat), and the lightning is most definitely a continuous attack. It doesn't help that damage reduction doesn't do anything, since lightning deals very small amounts of damage per tick—but very rapidly. And since 2 out of 6 classes are melee, and one of them is the resident tank, these flying mobs are incredibly hard to kill. Oh, and Polyps phase. (Notice a trend yet?) And bigger "Orbiles," called Bile Brains, spawn smaller Orbiles (Orbiles and Soul Reapers), which in turn spawn Polyps on their demise. Good times, good times...
 * And these are just the outright broken mobs.
 * X-Men Legends had normal foot soldiers that could chip off 70% of health after a single hit, and the majority of enemies that could kill you in ONE hit! Doesn't matter how many defenses you've built up, they will kick your ass.
 * The Force Unleashed. Pretty much any great enemy when you have to fight more than one at once. The first part of the Death Star level AT-STs and Purge Troopers and snipers all at once make for difficult gameplay. Then there are the Rancors on Felucia who take great delight in knocking you over, patiently waiting for you to get up and then knocking you over again a split second before you get control of your character back.
 * There aren't any Purge Troopers in the Wii/PS2 version, but the Jump Troopers and Heavy Troopers are probably just as bad. The former hovers around with a jetpack, repeatedly hammering you with rapid blasterfire and a freakin' flamethrower, and can take an insane amount of punishment (tough to hit, too). The latter wield electrostaffs that can block your lightsaber, and absolutely love to zap you in the back with electricity when you're busy fighting off the inevitable swarm of lesser foes that accompany them. And both frequently appear in groups.
 * The .hack series makes up for its lack of any single, solid example of this trope by making quite a few of the enemies you encounter borderline examples. Among these are the Mu Guardians that spam attacks freezing you in place until they finish, and consistently appear in groups to stack said attacks on top of each other. It's not as outright dangerous as it sounds, but every bit as irritating. It's in the third game, where Nega Guardians start showing up, that it descends into this trope's territory. Same basic idea, but those attacks are now far more damaging, and the battle is quite literally Unwinnable unless you use Data Drain, on each of them, individually... after which you must kill them AGAIN, though the second time Data Drain is mercifully optional.
 * Not to mention the Specters from the second game. In addition to having an annoying attack similar to the one used by Mu Guardians (though thankfully the Specters didn't spam it), they had HP that was absolutely ridiculous for the time, an attack capable of draining your SP, and an attack that was just under half as strong as the one used by Skeith (and Skeith being That One Boss on its strength alone, that is saying something). Oh, and they constantly appear IN PACKS.
 * Idols. They have the ability to resurrect any monsters you destroy. It gets worse when two of them are in the immediate vicinity of one another and you become forced to Data Drain one. Have fun getting through any Thunder areas in Infection, where it seems like every gate contains one.
 * Black Sigil: Blade of the Exiled: the pest spirits, oh dear Zodiat, the pest spirits. These little beasts have a spell that cause numerous status effect to all characters, but the most prominent one is berserk, which cause your characters to unable to take any action but doing physical attack to enemies. AND...that damn thing is immune to physical attacks. AND...there are only two items that can protect you from berserk, one is only gained from a secret character. The only good thing about it is that except for a round late in tournament, they are only found in the last dungeon, but better have Rogurd use Gold Toss or get someone with Vigil Ring / equipped when facing them or else one way or another you're going to get TPK (except if you have a weapon that can deal magical damage).
 * The ANBU in Naruto: Path of the Ninja. They can kill you instantly with their Silent Killing technique, enabling them to easily kill your party, and have much more HP than other enemies.
 * Just about everything in the iPhone/iTouch game SEED: Rise of Darkness, especially if it has ranged attacks. Lauza are particularly bad offenders, as they're listed as the same level as the almost pathetic Trampi (Level 10. Out of 99.)
 * Wild ARMS has a recurring gag with the Hyolkontons, Aliens with obscene hit points and their own version of Bad Breath, "Arc En Ciel".
 * In Skies of Arcadia and its Updated Rerelease, Skies of Arcadia: Legends, there are the Slothsters. While they look like giant green sloths, they happen to be very dangerous. Not only do they have ridiculous amounts of HP and high Defense, but it also dishes out devastating strikes and a breath attack that can cause Confusion. The developers also saw fit to give it the powerful Quake spell, which does, on average, 600 damage to EVERY party member. What's worse, if you can somehow manage to whittle down this behemoth's HP, it can also use Deep Sleep, which puts it to sleep and recovers a little HP every turn.
 * Golden Sun games never really focus on the monsters, more on the puzzles. Golden Sun: Dark Dawn is no exception... until the, which spawns a whole bunch of monsters that, if your party is not above L30 at least, will merrily feast upon you, mostly by virtue of being powerful, quick, and hard to kill in comparison to everything you've been two-shotting up until now. In addition,   have a vocal attack that can Stun, which they will spam, and   have an attack, Drag Down, that is a potential One-Hit Kill. I repeat, commons with a One-Hit Kill attack. Which they spam.
 * Wonder Birds are most likely an example, as they cast very powerful fire Psynergy, attack multiple times per turn, and are hard to escape from. To make matters worse, they will commonly get almost your entire party downed or close to it, then run away like a wuss.
 * Legend of Dragoon has these in the form of Psych Druids. God help you if you get these things in the red and don't finish them off before they get a turn, because they'll happily drop a psych bomb on you (effectively the strongest non-dragoon magic in the game, as well as being all-hit and non-elemental.) if you're looking for a way to run yourself out of angel's prayers and healing mists/rains that's the way. Beyond that, any mob that can do a One-Hit Kill (Death, Professor (also full of Standard Status Effects for extra "fun"), and some other annoying ones)
 * Arx Fatalis has Ylsides, which appear human but are extremely fast, hard-hitting, and well armored.
 * The blue blob enemies from Ys III. These things hit extremely hard with a wide hit-box, and can kill you outright if you're not leveled (or equipped) properly... which you probably aren't at that stage of the game.
 * Worse are the spear-toting enemies in the Cursed Mine, whose weapons have greater range than yours and deal massive damage. And you need to conserve your HP and ring power for the boss.
 * Darkstone features goblin bat riders. They have an inordinately high amount of hitpoints; their attacks are fast, accurate and powerful; they are immune to all elements except fire and they can spawn bats.
 * Drakensang has its share of though enemies in both games, including Harpies, Giant Crabs, Emerald Spiders, Stone Golems and Fire Spirits. The first two are severely annoying, as they can easily inflict wounds on your characters via physical damage, and it only takes five wounds to kill your character. Golems have a lot of health, are super resilient and hit like trains, and are immune to wounds. Fire spirits, while still manageable, have the irritating quirk of setting ablaze all characters around them.
 * The more advanced versions of the Bholdoms (wild boar-type creatures) in Ys VI, who not only hit hard and can take a whacking, but also inflict debilitating Standard Status Effects''. Also, the cave scorpions (Gilchas) in Mythos Path and Limewater Cave.
 * Musyamon in Digimon World 3 start as this. They are in the Gecko Swamp, with the only other digimon there being, well, Geckomon, who besides one obnoxious attack are pretty weak. Musyamon, though, have ungodly high offensive stats for any digimon at that point in the game, when your team will likely only be around level 15 or so. Also, thanks to the annoying escape mechanics, it's almost impossible to get out of the battle before it uses one of its strong attacks on you. Naturally they become a cakewalk once you level up properly, but until then, good luck.
 * The Dark Spire. Nearly every floor has at least two elite enemies. Nearly all of them are this, and there are some more common enemies that also qualify. Being a Wizardry clone this is normal and expected.
 * The best examples though are anything with a breath weapon. Breath weapons do damage based on the HP of the user to the entire party and can be used in the surprise round. It is not at all unusual for later ones to kill everyone before you can move.
 * Baten Kaitos Origins has Machina Auto-Turrets, which are found all over Tarazed. These little bastards are quick, hit hard with normal attacks, and have a nasty special that hits the whole party for varying amounts of damage, usually quite a lot. Just to add to that, they have quite a lot of HP. Frigid Queen's Festival is overkill for most normal encounters, but here it'll save you quite a bit of trouble. Thank god for After Combat Recovery.
 * Also in Tarazed, you find Prima Queens, which hit way too hard and explode after three or four turns unless they're killed. Just to add to that, they often appear with Dance Kings (which hit like runaway buses) and have a combination attack with them that takes off unreasonable amounts of health. Encountering two Dance Kings and three Prima Queens at once practically adds up to a full on boss fight. Frigid Queen's Festival won't save you if Guillo gets knocked out two turns in.
 * Any enemy encounter with a combination attack could really count, given as how those usually hit like freight trains.
 * In Icewind Dale and its sequel Icewind Dale II, you'll find many of these:
 * Salamanders: They have either cold or fire auras and always come in large groups. Their auras even damage you when they're non-hostile toward you!
 * Umber Hulks: Looking straight in their eyes will confuse you if you fail your saves. They're also backed up by Minotaurs.
 * Wailing Virgins: Inflict magic damage to all party members whenever they scream.
 * Harpies: Their songs charm your party, leaving you vulnerable to other monsters.
 * Crypt Things: Whenever they touch you, you'll teleport to a random part of the dungeon filled with other nasties.
 * Werejackals: Their gaze cause instant sleep to the victims.
 * Driders : They web you and call other Driders for help.
 * Ghosts in Dark Souls are frustrating beyond belief in spite of their low health and resistances: nothing can damage them except cursed weapons and cursed players, their attacks are fast, have a hell of a reach and ignore all armor on non-cursed players, and by virtue of being incorporeal, it's not rare for them to hide into walls where nothing can hit them and dogpile on the player in packs. Any corridor becomes a potential death trap when ghosts are around.