"Wake-Up Call" Boss

""You'll be having a really good time...and then all of a sudden this boss will kick your fucking nuts out through your nose.""

- Noah Antwiler of The Spoony Experiment on Persona 4's Shadow Yukiko.

Wake Up Call Boss is more or less a boss that symbolizes a massive Difficulty Spike, or at least symbolizes the point where the game stops going easy on you. At this point, everything you've learned but haven't really considered yet will be severely tested: Everything before was just getting you used to the controls, this is where the challenge begins.

Due to this, they usually appear early on, but can appear from early to early-mid game. They definitely shouldn't appear late. And it's not really That One Boss so much as it's very brutally drilling into you how to play: like a boss in a beat-em-up designed to very easily beat anyone who thinks they can button mash through the game.

Sister Trope to Early Bird Boss, a version of a Wake Up Call Boss that relies on the players lack of key items, spells, or metaknowledge early in the game in order to provide a challenge.

Compare with That One Boss, though this trope is specifically for bosses that appear early in the game and are merely a sample of the rest of the game's challenges. Also compare with Disappointing Last Level. Contrast with Warmup Boss, a first boss that frequently is impossible (or at least very difficult) to lose to. See also Hopeless Boss Fight and Final Boss Preview. Compare Skill Gate Characters, which are PvP characters/factions/whatever that serve a similar purpose in separating newbies from the experienced.

Action

 * Waka in Okami, because before that, you can just hack n' slash your enemies to bits close-range. Not Waka: he throws his sword(s) at you repeatedly, and you have to deflect them back at him with some skill to beat him.
 * The Spider Queen may come as a nasty surprise to new players as well, especially since she can stomp on you.
 * The Devil May Cry series featured some nasty first bosses, including the Phantom in the first game and Cerberus in the third.
 * No More Heroes: So you just got dropped into the game a few minutes ago, the controls on the High/Low thing are still shaky, and most of the Mooks you've fought have made you wonder what the blocking and emergency evading are for. You've probably only charged your Beam Katana manually once or twice so far, in safety after clearing a room. Then you fight Death Metal, who seems to block everything that isn't a counter hit, has a metric crapload of HP, and attacks with huge combos that burn through your battery -- if you're attentive enough to block. Oh, and halfway through, he produces two clones of himself who also have his BFS. Needless to say, once you learn Dark Steps and get better at the recharging, he's cake, but until then...ouch.
 * The real wake up call comes when you battle the notorious, the first boss where you have to carefully dodge, chase and wait for an opening. And demonstrates that bosses can pull out really strong attacks when they turn red. (The attack isn't a One-Hit Kill, but if you've taken any damage you're still going to die.)
 * The last Wake Up Call Boss is, proving that even if you've beaten the game twice, you haven't learned a damn thing.
 * Then we get to Desperate Struggle. The very first thing that happens? A ranking match against Rank 51. On Sweet, it's a tutorial fight. Anything more difficult? "Welcome to the game. Now die."
 * If Skelter Helter didn't mess you up for the tutorial, then the 50th ranked assassin, Nathan Copeland, most definitely will. If you haven't learned how to evade attacks, say hello to a rocket to the face. If you haven't learned to dodge when danger signs flash, say hello to a metal fist in the face. Plus, his arena becomes more and more dangerous as the fight drags on, forcing you to get used to being very attentive to your surroundings. Not to mention that blocking his attacks will, once again, burn through your battery like nothing else.
 * Murai in the Xbox version of Ninja Gaiden is the boss for the "tutorial level". If the mooks haven't taught you anything yet, then Murai will teach you not to button mash wildly or he'll block and counter with a throw. So you might think turtling works - WRONG! He'll teach you not to stand around aimlessly blocking with another throw. Start learning to roll and attack at the right times if you want to get past.
 * Alma also makes an appearance to just start smacking you down when you thought the game was done throwing curve balls at you. Doku, the Zeppelin Boss, your evil twin, and the second fight with Murai all qualify as re-wake up call bosses, to make sure you aren't falling asleep yet.
 * In Black, the game just rubs it in your face. So you finally beat the game? Good job, now go beat these three new HARDER difficulties!
 * Same deal with the first one from the Xbox 360 version of Ninja Gaiden II.
 * The Act III boss of the NES Ninja Gaiden. The Act I boss has a huge hitbox and is easily disposed of. The Act II boss has a big hitbox for his attack, but once again mashing the B button makes quick work of him. But the third boss? Mindlessly Button Mashing in hopes of doing damage won't save your ass; you now have to strategize if you want to deplete at least 75% of his Life Meter before Ryu bites it.
 * Viewtiful Joe is full of these kind of bosses, which can be very difficult if you don't know the tricks behind your character's abilities. This will eventually becomes clear once the bosses you fight suddenly start constantly reappearing. For example, the Helicopter, which will chew you up and spit you out if you don't know that, in slow mode, you can dodge and reflect bullets. In particular, if you don't already know you can knock the chopper's bullets back at it, you'll probably instead try to jump on top of it, right into the most dangerous part of the boss, and get a couple high risk, low damage hits in before jumping off to avoid injury. This makes the battle much, much longer than necessary and will generally lead to death. If you didn't get it the first time, then you'll probably have a really bad time stopping the chopper when two of them show up at once.
 * Also the fourth level boss Another Joe, who's basically an evil super-powered version of Joe that fights you in area with additional enemies and spike pits. Even if you made it through the other levels easily just by messing around, you actually have to know how to use your powers perfectly at this point to win.
 * Gold and Silver, the Macho Camp duo that serve as the first Mini Boss fight in God Hand, quickly establish the rules for boss fights in that game -- that they will suck royally for the player. Elvis, the actual level boss, later serves to cement that fact.
 * A case could be made for the randomly-appearing Demons to be the first real wake-up call, as the first one appears well before Gold and Silver, is nightmarishly difficult without using multiple God Reels, will be appearing at random and are, ostensibly, a basic mook.
 * Many, many early bosses from Capcom's brawlers qualify:
 * In Captain Commando the second boss, Shtrom Jr., teaches players to use quick attacks (due to his cunningly quick and long jumps) and that just mashing the punch button in front of bosses doesn't work if they break the combos so easily.
 * The Lizard Seemer stonewalls a lot of new Sin and Punishment players, since you have to use the projectile reflecting technique on him, which many players probably haven't even tried up until now. Trying to kill him with regular attacks will inevitably result in time running out.
 * Brad. Either get good at timing or look up how to turn on auto aim.
 * Heart Seeker, aka "stop relying on the reduced-firepower auto-aim mode to coast through the game".
 * Sin and Punishment 2 has Orion Tsang, the Stage 1 penultimate boss, who puts the "Punishment" in "Sin and Punishment" and shows you that the Nebulox battles are going to require some serious practice. For most of the battle, he shields himself so you can't damage him (in fact it's very easy to time him out the first several times).
 * Also, Hibaru Yaju, third of the Nebulox. She's tough mainly because she's the first boss that actually requires melee attacks to fight. For a lot of players, this is the first time they have to seriously use their melee attacks for something other than deflecting projectiles.
 * The first few minutes of Prototype give you A Taste of Power. The first boss fight with the Hunters afterward teaches you that you'll have to earn your God Mode powers. And if you underestimate Specialist Cross because he's a mere mortal, he will educate you, with an electrical staff enema.
 * Souther, the second boss in Streets of Rage, who swipes at you with his Freddy Krueger glove with RIDICULOUS speed and who can't be jump kicked.
 * Streets of Rage 2 has Jet, the stage 2 boss, who is hard to defeat unless you spam jump attacks.
 * Notably, Souther and Jet reappear TOGETHER in a later stage, making them a twofer.
 * The first boss in Streets of Rage 3 is Shiva from Streets of Rage 2. Oh yeah, and the difficulty only goes up from there.
 * If you haven't gotten proficient with Blood Raynes harpoon, the Sewers begin your Wake Up Call with charging suicide bombers, and ends with Playing Tennis With the Boss. Even if you are good with your harpoon, it's still That One Level.
 * The massive fire-breathing boss Bi Xie in Dynasty Warriors: Strikeforce is not only a Wakeup Call boss for the game, it's arguably a Wakeup Call boss for the entire series. It's not too hard once you know what to do, but if you go in expecting to do the classic Dynasty Warriors mindless hacking and slashing, you're probably in for an unpleasant surprise. Even if you're reasonably capable of handling Lu Bu, Zhang Liao and Diao Chan as they go in and out of Fury mode and gang up on you, as well as the swarm of tigers that first greets you when you enter the area, AND finally the giant boss itself - it's actually very easy to time out if you don't accomplish all this quickly enough.
 * The Qiaos tend to be this in other entries, simply due to the fact they are ridiculously fast compared to the most commonly encountered Notable Generals and juggle like crazy. Enraged Qiaos are even worse, but thankfully are rarely encountered in the core game. (They're more of a threat in the randomly generated empire building modes of XL and Empires.) Depending on which game, the worse of the Qiaos will change, since their movesets change a little every game. Huang Zhong may also count from 4 onwards, as while his guards engage you he will flee and spam his arrow shot special.
 * Gan Ning is notable for being a wake-up call boss AND being the Buttmonkey. After a certain stage, usually around the fourth for any Shu or Wu character, the CPU begins to use his musou far more frequently. For any who don't play this series, he does a quick dash with his sword held to the side, and it does the most damage in a single hit of any in the game. Most other musous are multi-hit crowd clearers, that do incremental damage and if you are juggled can sometimes be escaped from, but not this one. It fires off instantly, there is NO WAY to block it unless you were already performing your own, and if it lasts long enough he can drive around back and run you over a second time while you're still recovering. Once it touches you, the damage is already done, and it's immense, even on max-stat characters on EASY. In contrast, his normal attacks are almost all telegraphed and easily blockable. Essentially, if you always stay behind him he is one of the easiest to take down, but the battle can turn against you without warning. Depending on character merely being touched can do anywhere from 25%-60% damage to someone using no items.
 * Batman: Arkham Asylum pits the Dark Knight against Bane as the player's second boss and first true boss battle. If you're new or didn't get dodging and batarang throwing down with the Titan goon earlier as a taste of things to come, then Bane is rather difficult, since you not only have to dodge him, but the attacks of several Joker goons. This same method of defeating Bane applies to the Titan goons much later in the game. On a similar note, the first Scarecrow nightmare segment is relatively easy for a stealth segment and is pretty much nothing that a new player hasn't done before when they were the ones giving goons nightmares, but the second one is tougher, with fewer places to hide, longer stretches without cover, and enemies to fight.
 * Theseus may seem like normal boss fair for God of War II, but definitely serves as this your first time through Titan mode. He has attacks that kill in one hit and requires that you fight minotaurs while dodging those attacks. Up until that point, Titan mode is pretty intense, but the first time (of many) you fight Theseus, the game is just saying WELCOME TO TITAN MODE, MORTAL!!!! It's also of the 'trainer' variety, rather than the 'fake difficulty' variety. After learning the Titan mode MUSTS of compulsive dodging and blocking, he's not too bad.
 * Bayonetta has Jeanne. Even in her earliest appearance she's a Perfect Play AI, so needless to say if you haven't got the hang of dodging (and therefore Witch Time) yet, she will hand you your ass on a silver platter.
 * And that's on Normal mode. On Hard mode she starts attacking from a distance by summoning Giant Feet and Fists Of Stomping without any warning and sometimes repeatedly, so you can't let your guard down for even a second. In Non-Stop Infinite Climax she is even more GFS-happy and you can't use Witch Time! So basically, in each difficulty, she makes sure to be a Wake Up Call Boss again and in a different way.
 * Bahamut, in Lord of Arcana. As the third boss he is much more difficult then both the previous and next boss. Not only does he have a one hit kill attack (notably, the at this point infamous "Mega Flare") when you first face him, if you have not learnt how to dodge and block well, you will die. Coupled with the fact that he has much higher health then any boss so far, the outcome of the battle depends on the idea that you know how to weaken him to stop some attacks and that you know how to heal yourself at the right time.
 * Notably, unlike the last two bosses in which the game outright tells you that they have destructible parts, Bahamut's hint can essentially be summed up as "Megaflare hits the center of the stage". The game also does nothing to inform you that Bahamut's wings are destructible, but most players might be able to guess that. His tail, on the other hand, is not so obvious, taking significantly less damage then the rest of him and almost encouraging you to avoid it. Bahamut is also the first boss in which player's might find that, to their horror, enemy bosses can, and will, flee the battle if it goes bad for them. Most players don't have the resources to even attempt to fight Bahamut again, and the mission does not end once Bahamut has fled. Instead, he appears somewhere else on the map. Most players will probably restart their PSP's and try again later to avoid losing all their healing items.
 * And to further compound problems, unlike the last two bosses who were quite effectively crippled when their destructible parts were destroyed, Bahamut goes on to prove that he can continue to fight without half of his tail and shredded wings with no real loss in fighting prowess.
 * Touhou usually does this for stage 4 bosses, but special mention goes to Parsee Mizuhashi, the second boss of Subterranean Animism, who very quickly establishes that the bosses in this game are significantly harder than usual. Parsee has both shots that chase you around the playing field and a doppelganger attack; tactics normally reserved for late-game bosses. And the game's bosses do not get any easier from here...
 * Good old Sakit from La Mulana definitely counts. He's the boss of the Mausoleum of the Giants, and he's here to tell you that bosses aren't going to go down as easily as Amphisbaena did. He's only vulnerable to attack after using his Rocket Punch attack, he's immune to all subweapons, and his main attack fires large magic projectiles that deal way too much damage to your pitiful HP. For a veteran, it's child's play to skip around Sakit, but new players are likely to run straight into him.
 * Atlas from Astro Boy Omega Factor. Attempts to go charging in, lasers blazing (like a first-time player might have done until now), will get you killed before you know what the heck happened. Atlas has jet-dashing punches, and a nastier version of Astro's Arm Cannon that takes up nearly the entire screen--and once he gets down to half-health, he replaces that move with a constant electric stream below him. He's not that difficult, but you'll need to get a good grip on battle techniques (dashing and knowing when to fire EX moves in particular), to stand a chance.

Action-Adventure Game

 * The Legend of Zelda had Gleeok from Level 2 in its second quest. Like the Genie, mentioned right below, you'll likely be ill-equipped and it teaches you that you have to stock up to survive later fights. And if you don't have the Blue Ring, its fireballs deal a full heart of damage.
 * The early morning receptionist for Link's Awakening is the Bottled Genie. He throws fires that also deal a full heart of damage which are hard to dodge thanks to the iffy underwater controls, and the fact that you won't be used to his attacks at first (or at all) means that you'll get your power knocked out of you before long. On top of all this, he has a second phase...that scrolls.
 * Skyward Sword introduces you to Big Bad Ghirahim as the boss of the first dungeon. Up until then, you can get by OK just by flailing your sword around at most enemies. If you do that against Ghirahim, he will utterly destroy you. And talk smack at you for playing like crap.
 * Donkey Kong Country 2's 2nd boss, Krazy Kleever is probably this. He starts out fairly simply, shooting a couple fireballs at you and slowly chasing you down a line of hooks, but after you hit him three times, he sinks into the lava, faking death for about half a second before he bursts out, lunges at you, and proceeds to chase you across the hooks (now at several vertical levels) at a much quicker pace. Oh, yeah, and now he flies. Not That One Boss (especially not compared to, say, K. Rool himself), but still dangerous enough to cost you a few lives the first time you fight him.
 * Elite Krotera, the first boss of Iji can easily wipe the floor with you. He's got powerful weapons, and the floor sprouts turrets that can eat through your armor like candy. As the the creator's speedrun video shows, however, with the right skill loadout you can kill him before he can get off a single attack. It's fun to watch.
 * Wendy O. Koopa from Super Mario Bros 3. Unlike her younger brothers Larry and Morton, Wendy's projectiles actually bounce off walls instead of disappearing, making her extremely hard to defeat.
 * The first boss of Conker's Bad Fur Day, Haybot, may qualify as well. At first, it seems like the characters (Conker assisted by Franky the pitchfork, in this case), simply have to hit the hay-covered robot three times while dodging its attacks. But then the boss breaks the floors out of rage and all of them fall into a sewer basement where the battle turns into a nasty Didn't Need Those Anyway scenario. The boss loses parts of its body as Conker and Franky continue pressing the red button behind its body, which in turn can only be done after luring the boss into water (after, in turn, luring the boss's missiles into some pipes to break them). When Haybot is complete, it attacks by squashing the characters with both hands. When one of those hands is gone, it attacks by seizing them and then throwing them away. With both hands gone, it squashed again the characters, but with its own metallic base. With the rest of the body gone, the boss is simply defeated, but then our Anti-Hero has to escape from there before it's too late.
 * The first miniboss of Henry Hatsworth in The Puzzling Adventure, Weasleby's mech. Remember when, early on, it told you how to power up your projectiles using the puzzle mode? You're gonna need that; getting within melee range is very risky and unpowered shots do pitiful amounts of damage.

Puzzle

 * In Puzzle Quest Challenge of the Warlords, most of the enemies you face can be defeated within a rematch or two (or on intentionally tough sidequests you can come back to later). Then you get to the first boss, Dugog, the two-headed ogre. Not only is he significantly stronger than any other regular enemy you can face up this point, he sports a spell (Double Roar) which can easily erase all your hit points and a weapon that randomly does near-triple damage. Not to mention you face his early enough that skill alone often isn't enough to take him down.
 * Lady D in Henry Hatsworth in The Puzzling Adventure. The game up to her is fairly simple, but Lady D herself can be quite a challenge to a player who's new to the game. Once you get the hang of fighting her and dodging her attacks, she's a piece of cake (pun intended.) The rest of the game gets MUCH harder pretty quickly, and while the second boss is a joke, the THIRD boss is pretty much That One Boss.
 * Dr. Robotnik's Mean Bean Machine has Frankly, the second opponent in the game. To newer players that aren't used to chaining yet, Frankly's stacking pattern is punishing, as uninterrupted, he will constantly get chains that will rain blocks on the player's side. The game only gets harder from there.
 * The Immoral Beast in Catherine is the second boss of the game, but it will take a player off guard. It is surprisingly fast, has a move that reverses the controls, and, more or less, is the first time a player really has to think on their feet. Making a wrong move can easily spell doom. Not only that, but there are trap blocks, which one can easily forget about and get skewered by.

Rhythm Game

 * in Guitar Hero III Tom Morello serves as a wake-up call boss, and not in a good way. He demonstrates how boss battles in this game will be determined by random chance. Surprisingly, though, he is actually easier to defeat on higher difficulties, seeing as in Easy and Medium mode the notes are simply stretched too far and few in between for players to be able to do significant damage by making him miss these notes.
 * In fact, the boss battles are tough enough that if you lose enough times in a row, you can skip them (except for the Final Boss; for him you're going to need some luck and a whole lot of skill... or just ridiculous amounts of skill).
 * In DJMAX Technika's Popular Mode, each stage has a different songlist, with the minimum song difficulty getting higher with each of the three stages. If you're new to the game, you'll most likely pick "Jupiter Driving" as your stage 3 song. It's a level-4 song, is the easiest stage 3 song, and teaches you to handle patterns in which the timing line moves at double speed.
 * "Area 7" on the first stage is a song whose repeat notes look awkward. You'll need to understand their rhythm rather than just relying on the timing line in order to survive this song.
 * Dance Dance Revolution in its earlier years brought us "Paranoia" on Basic, a level 6 (on the pre-Dance Dance Revolution X scale). It's 180 beats per minute (which when it first appeared on DDR 1st Mix made it the fastest song in the game) and features a handful of eighth notes (including a nasty "jackhammer" note section at the end). If you can clear this song, you're on your way to taking on more difficult songs.
 * Space Channel 5 has Morolina for Part 1, and Kin Kon Kan in Part 2.
 * "Canned Heat" in Elite Beat Agents on Cruisin' mode. The songs before it have relatively simple and consistent rhythms, but "Canned Heat" has a strange disco beat with syncopated rhythms everywhere. Because of this, most players mark it as the first song they ever fail. In Sweatin' and Hard ROCK! modes, it can happen as early as "Rock This Town".
 * Gitaroo Man has the first battle against Ben-K, which is purely guard phase (read: hitting a flurry of notes coming in from all directions). The notes come at you fast and thick, with a rather irregular rhythm, leading most rookie players to complete it with barely a sliver of health to spare if they pass it at all. In Master Play, it can happen as early as Flying O, which, mind you, is the second stage.

Role Playing Game

 * A quintessential RPG example is Brock from Pokémon Red and Blue. Although he's far from being the most powerful Gym Leader, Brock is still unexpectedly strong enough to catch most off guard. Firstly, most if not all of the Pokémon catchable before the battle (Bug, Normal, Flying, Poison and Electric types) are weak/powerless against his Rock/Ground Pokémon, leaving the starter to be the one to do most of the work. However, if the player powers through Viridian Forest without bothering to grind, only fighting the pretty easy bug catchers in the forest, then their starter may not be strong enough to stand a chance against his stronger Pokémon, especially if they didn't learn the type-specific move that the starter learns after a few levels and which can be used to super-effective him to death. In addition to that, since several fans thought that the fire-breathing Charizard was way cooler than the rest, they had the additional problem of having their starter being weak to Brock's Rock-type attacks as well with no recourse other than Level Grinding. Tough luck, kid.
 * The remakes fixed it by allowing a Mankey (Fighting) to be caught early on in Route 3, which can deal super effective damage against Rock types.
 * Pokémon Black and White has the Striaton Trio (Cilan, Chili, and Cress), WakeUpCallBosses who are designed to screw you over, no matter WHICH starter you chose! Each one has a signature Pokemon that will have the type advantage against your starter Pokemon (Pansage for Oshawott, Pansear for Snivy, and Panpour for Tepig). This is also where you first run into the new game mechanics for certain abilities this gen, as their Lillipups will use the Retooled Pickup ability to heal themselves with the berries your Pokemon was just holding to heal itself if you gave it the Oran berries you won from Cheren.
 * Heck, pick up Chimchar in Diamond/Pearl and try to beat Mars the first time. Unless you deliberately overlevel Chimchar, her Purugly will wipe your party.
 * Gold/Silver had Falkner. Up until this point, you've probably curbstomped every trainer you've fought. Your Rival? The Sprout Tower? Those are easy. If you picked Chikorita as your starter, its got a natural disadvantage against his Flying-types. Picked Totodile, nobody has an advantage. Picked Cyndaquil? Mud Slap can destroy you with a single hit.
 * If Mud-Slap can fall your Cyndaquil in one hit, you must be training your Pokemon wrong. The most powerful move Falkner can bring on you is Gust. With same-type attack bonus, this move has a base power of 60. Mud-Slap does not gain same-type attack bonus, and even with damage bonus, the base power is only 40. Even Tackle has a base power of 52.5 with same-type attack bonus. The Tackle will kill you before the Mud-Slap can. Remember that all types mentioned (Normal, Ground, Flying) were classified as physical attacks in Gen 2.
 * The Dev Team Thinks of Everything: In the the house next to the Pokemon Center in that same town, a person will ask you to trade a Bellsprout (Very easy to find in the field just before the town) for his Onix (Rock/Ground). Guess which type is super-effective against birds?
 * Falkner serves this role again, but in a different way, in HeartGold and SoulSilver'. This time, he serves as an alarm clock for veterans re-playing the game who expect everything to be the same. Up until Falkner there have been a few changes from the originals, but when you reach him and realize his Pidgeotto took a level hike--from 9 to 13--and then watch Pidgeotto heal itself using Roost, you realize the game is broadcasting a big hint with the subtlety of a megaphone: "Boss fights in this game aren't going to be retreads of the original."
 * Ruby/Sapphire has Roxanne. If you picked Mudkip, you'll be fine. Torchic, on the other hand, will be destroyed instantly, and Treecko, despite the type advantage, won't fare much better. For starters, Roxanne's Nosepass is a pure rock type, instead of a dual Rock/Ground, so your damage is only doubled. Doubling is still good, but the only grass move you'll probably have at this point is Absorb, which is pretty weak, and Nosepass has better stats than Treecko. Fortunately, you can pick up some water and grass types before this gym, and trade for a Fighting type Makuhita, or you can evolve your starter and stand a better chance.
 * Miror B. from Pokémon Colosseum is annoying, but his Ludicolo squad lacks any real offensive power or levels to be a real threat. The second and third bosses, however, are both ready to prepare you for the game in their own way:
 * Cipher Peon Skrub will tank with Clamperl and Wynaut (the latter of which will return fire like the Game Breaker it is) while thrashing your team with Geodude's Magnitude and his Shadow Hitmontop. You can't rely on pure power to overcome Clamperl or Wynaut, because if you do Geodude and Hitmontop will make you suffer. Hitmontop in particular is the first time in the game where an opponent's Shadow Pokemon can really wreck your team, forcing you to play strategically, especially if you plan on enduring attacks while trying to Snag it.
 * And if you didn't get the memo from Skrub...one dungeon later, Dakim will really bitchslap you awake. His Earthquake+Protect combo will decimate an unprepared team, and that's nothing compared to the Oh Crap when the player realizes he has a Shadow Entei. Dakim teaches players the following: First, that since every battle in Colosseum is a double battle, you need to keep an eye on both your Mons. Second, that bosses will use actual strategies against you, and you'll need to do the same or get used to whiting out. And third, that enemy Shadow Pokemon are really dangerous and that you stand a legitimate chance of them fainting (either from recoil due to Shadow Rush, or as collateral from the nature of double battles) before they are Snagged.
 * So, I see you bought Demon's Souls to see what the fuss was about? And, glory be, you breezed through the first levels of like they were nothing. Your shield is just that broken. Then comes the Flamelurker, a fiery monstrosity with attacks that pierce your shield's defenses and BREAK them. And on top of that, they are impossible to dodge without a perfectly-timed roll with light equipment. The only way to survive this fight is to learn the importance of choosing your equipment to fit the mission better, eliminate extra weight to be able to roll and to not depend too much on brute force and endurance.
 * Another example may be the very first boss in the tutorial level, which follows a level with very weak enemies that don't look too menacing and who are stopped in their tracks by your shield. Then comes this towering ball of muscles with a giant axe, huge range, broad swings and the strength to crush you and your shield in one hit. And did I mention it takes about one hundred hits to kill? And, if you do manage to kill it (chances are you won't even touch it) you are then taken to another area which culminates with you getting punched to death by a monster five times bigger than the boss before. And then the game feels the need to cut down your HP to half till you beat another boss.
 * And then there's Phalanx, the first true boss of the game. He covers himself with shielded mooks, which are only vulnerable to fire and magic (both of which you'd only have if you started as a mage or a noble) unless you attack them from behind, which is fiendishly hard to do, and if you're a physical attack character, this means you're going to need to use some of the items you picked up in the level, or you'll just be engaging in futility. Oh, and you can't level up until AFTER this battle, so if you used up all those fire bombs and turpentine you'd gathered through the level, save yourself a headache and start over, because those shielded mooks will own you, since in addition to the dozen that cling to the boss, there's a dozen more roaming the area, ready to make you a pincushion with their spears. Oh, and they have ranged attacks. Nobody ever said this game is easy.
 * How about Earthbound? Frank Fly might not seem so harsh to a beginning player... until they have to fight his "Frankystein Mark II" immediately afterward. This fight mostly serves to teach you about the rolling HP meter; without exploiting that, you're in for a world of pain.
 * For the above's sequel, Mother 3: Mr. Passion is generally the first boss where players realize just how vital debuffs, status effects, and item strategies are. Level Grinding and the Thunder Bomb trick will only get you so far here.
 * So, you breezed through Mr. Passion without too much trouble. Well, congrats. A couple chapters later, however, you're gonna meet the Jealous Bass, a tough Flunky Boss who works with his flunkies to hit Lucas and Boney multiple times per turn. Without finding the right combination of items and Lucas' limited PSI, you'll get stomped.
 * Castoth, the first boss of Illusion of Gaia, is frequently cited as one of the game's most difficult. This continues the trend set by predecessor Soul Blazer, which features a nasty first boss that becomes the Bonus Boss in Illusion of Gaia.
 * Castoth isn't really that difficult by Illusion of Gaia's boss standards--the Vampalso, though at least his HP is low enough you could rush him to death and hope for the best.
 * Final Fantasy I: Kary/Marilith is devastating to an unprepared party. In addition to having to make it through the lethal-floor filled Volcano, Marilith doesn't have any elemental weaknesses (not even Ice, which would make too much sense, I guess), and can land upwards of eight hits, enough to seriously injure a heavily armored Warrior and more than enough to kill a squishy mage. Unless you're willing to try a Useless Useful Spell (which is truly useless in the original NES game because it doesn't work), you're in for a very tough battle.
 * The second battle with Scarmiglione in the DS remake of Final Fantasy IV can be seen as one of these. While some bosses up to this point may have been somewhat difficult, this is the first boss that introduces you to the fact that major boss characters in this game have whole-party counters which trigger when you try to exploit their weaknesses or use the same tactics from the SNES/GBA versions of the game, and really forces you to start thinking more strategically.
 * Final Fantasy VI: Number 024, fought in the Magitek Research Facility. It's a cakewalk if you know what to do. However, for newer players (to the game or the series) or if you don't pay attention to its Barrier Changes, it's going to be an uphill battle. The fight teaches you why it's important to Scan for bosses' weaknesses.
 * Final Fantasy IX has the Plant Brain, which uses blinding attacks on your mostly melee-oriented party and does some pretty bad damage. Luckily, there's a free health and MP restoring spring in the room before it.
 * An even more egregious example is Black Waltz 1, only a couple of fights after Plant Brain. He begins the fight by summoning an ally... and you have to fight the pair of them alone. Fortunately, you should be close to Trance at that point...
 * Final Fantasy Tactics
 * The fourth scripted battle, the Dorter Slums, is a Wake Up-Call Battle. This is the first battle where your enemy has a specialized setup, with a knight, two black mages (which, if you're unlucky, will take advantage of the rain and use Bolt), and at least 4 archers, one of them at the highest point of the stage (though oddly enough, one of them is unarmed). This battle tends to be a wall for many new players, and seems like it's telling you that future battles won't be messing around, either. And they don't ease up.
 * There's also Wiegraf, early in Chapter 1. Granted you did get to see his Holy Sword attacks demonstrated by Agrias in the prologue, but he's the first encounter you have with an enemy who can use abilities that the main character cannot learn, no matter what. The battle also serves as a Chekhov's Gun in this respect, since he becomes That One Boss later in the game by being incredibly tough, one on one, and a Sequential Boss to boot.
 * At least until Thunder God Cid (his in-game name) shows up about 2/3 the way through.
 * There's an earlier Wake Up Call Battle, though it's more for the naive or the reckless: Algus (Argath in the remake)'s rescue. If you choose to save him, he becomes almost suicidally reckless, and if he falls it's game over. The best option here if to callously disregard Argath's situation and choose to kill all the enemies, at which point he becomes almost ridiculously cautious, running from battles as much as possible, but making you a jerkass in the process.
 * FFT has a nice few of these. If you're underleveled and don't know what you're doing - (e.g. just rushing through the required battles with the starting classes or without any good abilities) you can easily get killed during your first battle at Dorter. Knights coming at you from the front, with Black Mages backing them up and firing AoE spells at your party, while a pair of Archers are stationed up at the top of a building that's several stories high and takes about three turns to climb. And your party is at the bottom, just at the edge of their attack range - which means your Squishy Wizard (if you brought one) can be on the ground very quickly if you deployed him/her in the wrong place.
 * Final Fantasy X has Sinspawn Gui. It's fitting: since Operation Mi'hen was something of a Wham Episode for the game, the gameplay follows suit with a boss that makes the player realize for the first time how much consideration you must give to the CTB system in your tactics. If you just spam your overdrives, you let Gui get more turns to abuse your team with poison. You have to be careful about who's using their turn for what and against which part of its body.
 * Final Fantasy XIII
 * Aster Protoflorian exists to make sure that the player gets the new battle system, EVERY. SINGLE. FACET OF IT. Don't bother or know how to take advantage of elemental weaknesses? You die. Don't optimize class roles to boost chain bonuses? You die. Don't know how to switch classes on the fly for sticky situations? You die. Don't believe that buffs are necessary? You DIE. This boss is so unforgiving while enforcing the nuances of XIII's battle system that to some players it approaches That One Boss territory.
 * Odin is the choke point of a lot of people playing Final Fantasy XIII, as the Vile Peaks dungeon is where the game requires you to think your way through battles rather than pound the X button. Specifically, you have to figure out that Odin is going to attack Hope, and only Hope. And Hope is not good at taking attacks. If you Libra Odin, you'll find that he "Yields to those who amass chain bonuses" and "Yields to those who heal the wounded." By the second one, you'd think simply switching to Medic and keeping Hope alive would do it. The problem is this is a Timed Battle, and if you focus only on healing, you'll run out of time. You need focus on both healing and attacking simultaneously. Plus, a big part of the battle is figuring out that Ravager/Ravager is more efficient at raising his chain gauge than Commando/Ravager (which has probably been your go-to for all attacking before now)
 * Earlier than that, though, is the warmech in Lake Bresha. He is there to teach you how to Paradigm Shift (FFXIII's main combat wrinkle, basically shifting character roles on the fly to cope with that situation). He teaches you Paradigm Shifting by killing you dead if you do it wrong. He's not nearly as brutal about it as Aster Protoflorian above, though.
 * When you arrive to chapter 12, ground up from all the sidequesting in chapter 11, it looks like all the enemies you encounter are cakewalk--for a while. And then, without any advance warning, you are pitted against Adamanchelid, one of the monstrosities you did so well to avoid on Gran Pulse, who kills your party with four stomps. Until you learn to spam Daze on it like no tomorrow, you just die, again and again.
 * Lost Odyssey: First real "boss" is just a kind of gryphon-thing, which really isn't very impressive -- but considering your very limited selection of skills, weapons, characters and spells at the time, he ends up wiping out most players the first time they meet him. And probably the second too. The main difficulty with this boss is that it pretty much requires you to make use of the Guard Condition mechanic, which is easily ignorable up until then. Going on the offensive is suicidal--the trick is to focus on defense and keep the Squishy Wizard alive long enough to do the real damage.
 * Mistwalker seems to love this trope, as the same thing is true of their other game, Blue Dragon. The first real boss is a dinosaur/dragon thing. If you've gotten the hang of combat and are sufficiently leveled, it's not too hard, but if you're not ready for it, it will absolutely slaughter you without compunction or remorse.
 * Suikoden I:
 * Almost everyone agrees that the Zombie Dragon wasn't just a hard boss for the level, it's a really hard boss in general. It attacks your whole team at once, does a large amount of damage, and has a lot of health. If anyone in your team dies, or if you don't distribute potions, gem (and odds are, at this point, you don't).
 * Similarly, the fight against Sylph is going to knock you good if you can't coordinate your party, as they're the first of only a handful of multi-part bosses where all enemies are of roughly equal strength, rather than being a Flunky Boss. While you're focusing on one, the others can easily sneak in behind and attack your back-row characters.

This is especially true if you elect to fight Sylph before the events at the Tower of Salvation, as you will not have many of the advanced techs needed for such a complicated fight, such as Raine's mid-range and advanced healing arts.
 * Secret of Mana,
 * You literally cannot lose against the first boss and the second is a piece of cake too. And then there's Spiky Tiger. Ow. Spiky is considered by many players to be one of the toughest bosses in the game. This is probably due to his ability to inflict the burning status on your characters (paralyzed and taking continuous damage) as well as knocking them out with a hard-to-avoid physical attack. He also regularly jumps to the raised platforms on the sides where he can only be hit with the two ranged weapons you have--which, being weaker than the melee weapons, you may not have bothered using them, meaning you won't even have unlocked the charge attacks. AND you don't have any magic of your own yet.
 * When you first get to the ice country, you'll encounter a mid-boss, Boreal Face. The wake up call here is that once you obtained magic, most bosses were about spamming it until it died. Boreal Face however as an absurdly high magic defense, and the most you can do against it with magic is 20-30 HP and it has around 1100HP. By the time you absolutely run out of MP for attack spells, Boreal Face will have over half of its HP left.
 * Seiken Densetsu 3
 * At approximately the mid-point of the game, there is a series of seven god-beasts that need killin'. They are always of increasing difficulty, but the order is up to you. Regardless, the jump somewhere between the second and fourth god will always be HUGE. This serves to force you to attain or come close to attaining your first Prestige Class.
 * Before that is the furnace demon Genova. It has considerable spell firepower and two resilient mooks helping it. It can easily overwhelm a novice, but if you know how to control your fighters and bought power-up items in Byzel beforehand, it'll be a cakewalk.
 * And even before that there's a pair of Machine Golems. These will quickly teach you that direct damage spells are not the Game Breaker they were in the previous game.
 * The first battle with Mid-Boss in Disgaea Hour of Darkness. While neither he nor his troops are unusually strong, the battle does mark the first time where understanding both throwing and geopanels (two things which you can breeze through the first few stages without using) are vital. Without these, it's likely that a first-time player will have half of his army blown away by the geopanel-boosted Archer and Mage before he gets to his fourth turn. That said, even if you lose you get to see a unique ending.
 * Diablo features The Butcher, who is an extremely tough opponent for the part of the game, being very fast and capable of dealing huge amounts of damage in close combat. He quickly becomes That One Boss to lower level characters because the only way to beat him safely depends on the randomly-generated terrain spawning in such a fashion to let you plink him to death at range. Thankfully, he only has a 50% chance of appearing, and drops a nifty unique axe when he finally goes down.
 * Diablo II, had this at several points in the game, many of which were lethal on the Hardcore difficulty, and were designed to screw over those with poor gear or bad skill distribution.
 * Good luck taking down Blood Raven if you're a melee fighter. In fact, given her speed, powerful ranged attacks and the minions she calls up periodically to harass you, good luck period.
 * Duriel. So you're a ranged class and you've been running away shooting over your shoulder all the time, eh? You think you can kite or outrange every single monster in the game, eh? You think that hit points are useless because nothing comes close to you, eh? You think if you ever come close to dying you can always run away, eh? And the game would never put you in an inescapable sardine can with a boss that will charge you for an instant kill if you get too far away and has an unresistable slow aura? Ha!
 * As of v1.13 at least, Duriel no longer uses charge, but his (un)Holy Freeze aura pretty much makes you hardly able to retaliate effectively as he dices up your character in short order.
 * In Chrono Trigger, the first boss, Yakra, can quite easily be brute-forced even if you don't understand the complexities of the combat system. The Dragon Tank that comes about an hour later, however, is a Wake Up Call Boss. Its parts must be attacked in a specific order (head, wheel, body), and as it can heal itself, you have to proceed intelligently rather than keep attacking until it dies.
 * And then there's 2300 A.D. which is a whole Wake Up Call Area telling you "No, you can't just bash A to win".
 * And again once you reach 12,000 BC. Heck, there's a whole series of Wake Up Call Bosses.
 * Final Fantasy Legend II (aka SaGa 2) features several of these. It's possible to get pretty far with a weak party by relying on NPC guest characters, running away from battles, saving a lot, and sheer luck. Then the player runs into Venus, who will wipe the floor with any player that's been neglecting to upgrade the party's equipment and its stats. Much later, near the end of the game, the fight with Apollo presents another brick wall.
 * Gen-Bu from SaGa I was likewise a sudden jump in difficulty. And it was possible to save to the game's single save slot after triggering him, and just before fighting him, rendering your game borderline Unwinnable.
 * The Mark VIII Salamander at the beginning of Rogue Galaxy has three stages to break through, and your party members force you to fight solo for the final phase. Hope you stopped to buy extra healing potions.
 * The bosses in Shin Megami Tensei Nocturne are generally Nintendo Hard, but Matador is the first boss that really gives you an idea as to what kind of lengths you'll need to go to in order to beat some most of the bosses in this game. Not only do you need to recruit and fuse a team that is specifically resistant to one element, but one of them needs to have learned a certain move to counter Matador's main ability, Red Capote. And God help you if you don't have a whole-party-heal spell yet.
 * World of Warcraft has wake-up call instances (dungeons). While the earliest just contain slightly tougher monsters, with bosses almost indistinguishable from the monsters around them, one of the first to step beyond this was Shadowfang Keep. Packed to the gills with monsters that drain life, summon allies, become magic immune, curse, stun, slow and silence. And has a boss that teleports around the room shooting at you, and transforms one of the party into his worgen slaves.
 * Lord Godfrey, Arugal's replacement, uses a Pistol Barrage that kills anyone that stands in it, puts DO Ts on random players with Cursed Bullet and summons adds. He's arguably as hard as his Heroic version.
 * Another shock is the mid-level Zul'Farrak instance, where a bad pull will lead to half the dungeon coming down upon you. Much of the stereotype of Death Knights as bumbling idiots comes from the fact that they begin at a higher level than these instances, so the player hasn't taken the Death Knight into any instances at all when everyone else is supposed to be on the ball.
 * This is Hogger's entire claim to fame.
 * Progression raiding is sprinkled with what are called "gear check" bosses; no matter how clever you think you are, you simply have to have a basic level of stats or these guys will pound you into the dirt.
 * The prime example of this being Patchwerk, from Naxxramas. He does only two things: Beat the tanks, and beat the tanks harder once he's below 5% health. He has a short enrage timer though, after which he will mercilessly oneshot anything that happens not to be himself. So you are standing there, and the only thing you have to do is beat him hard, so he falls before the enrage is hit. He is meant to be a check, if you gear suffices to bring him down. If not, the rest of the bosses would have murdered you anyway.
 * Each time for new expansion, the new dungeon accesible immediately to the player has quite challenging bosses. In Burning Crusade, they give you Vazruden and Nazan in Hellfire Ramparts and Broggok in Hellfire Blood Furnace. And in Wrath of the Lich King there is Keristrasza in Nexus.
 * Similarly, at max level (70 in The Burning Crusade, 80 in Wrath of the Lich King, and 85 in Cataclysm), characters may begin entering heroic dungeons, which are powered up versions of the standard ones, as well as raid dungeons intended for 10 or 25 players (the original game had 40-man raids). These are significantly more difficult than normal dungeons in terms of the level of gear needed to survive, the skill and coordination required of players, and often the challenge of getting a group together in the first place. Also, raid dungeons lock players into a particular "instance" of that dungeon for a period ranging from 3 days to a week, making consistent and prompt attendance essential. The result of this is that new players who have never tried to tackle endgame content face a brutal learning curve, especially if they can't get into a guild that's been raiding for a long time and can train them. In the original World of Warcraft, this dungeon was Molten Core; Karazhan served the function in The Burning Crusade, and Naxxramas is the Wrath of the Lich King equivalent, although Blizzard has made a conscious attempt to lower the bar to raiding by making the latter relatively easy.
 * Speaking of Naxxramas, the second boss of the Construct Quarter Grobbulus definitely qualifies, since players will often elect to face him early in the dungeon. Although previous bosses are designed to be beaten through sheer power, Grobbulus lays deadly patches of poison gas where he stands and summons additional mooks throughout the encounter, necessitating strategic movement and co-ordination. Gluth and Thaddius serve to drive Grobbulus's point home (although many guilds will elect to fight Gluth and Thaddius close to the end).
 * Almost every starting zone also offers a Wake Up Call Boss in the form of a quest requiring the player to kill an elite NPC that is significantly more challenging than the normal enemies the player has fought to that point. The most well known of these is Hogger, a level 10 mob in Elwynn Forest, who is so infamous for slaughtering newbies that he's become a Memetic Badass as well as a That One Boss.
 * Sunwell Plateau could be described as an entire wake up call dungeon, but specifically the first two bosses, Kalecgos and Brutallus, who were both significantly harder than Illidan (the final boss of the dungeon before SWP,) forced a large number of players to learn to play or go home. Countless guilds maybe scraped a Kalecgos kill or two but failed to make so much as a proverbial dent in Brutallus, causing them to give up (or perhaps even just break up entirely.) M'uru had a similar effect on the guilds that made it to him.
 * A late expansion example would be the trio of dungeons released in "Fall of the Lich King", at a point where everyone got used to breezing through dungeons even on heroic difficulty on autopilot. Many of the bosses could be considered this, depending on how long it takes for the player to realize that they have to pay attention this time. The Devourer of Souls would be the first, often catching players off guard when he uses a new attack at low health, a wandering beam that swiftly kills anyone standing in it, as well as making people kill themselves with his mirrored soul spell. All of the bosses in Pit of Saron count to some extent as well.
 * The abominations, Festergut and Rotface, are this for Icecrown Citadel. The former is a DPS race that requires the party members with the spores to stand in the right place to spread them to the rest of the raid to avoid a wipe when he uses Pungent Blight. The latter requires players who get Mutated Infection to kite the slimes on them to the person with the large slime without running into anyone else's slime on the way, in order to control the rate at which large, explosive slimes form. In both of these, all the players have to know what they're doing in order to survive, and many Icecrown Citadel raids do not get further than these two.
 * One of the most notorious examples came pre-expansion in the form of Blackwing Lair. The very first encounter is Razorgore the Untamed, the second hardest boss in the instance. Note encounter, not simply first boss. Razorgore requires an unbelievable amount of guild coordination and several good tanks that can reliably hold off multiple enemies at once. If you manage to beat Razorgore, the very next room is home to Vaelastrasz the Corrupt, the hardest boss in the instance (including Nefarian). Vael requires so much fire resistance that he makes Ragnaros look like a cigarette lighter in comparison, and you only have a very limited amount of time to kill him, requiring the raid to do a huge amount of damage. Blackwing Lair was a notorious guild killer back in the day. Even with Wot LK and Cataclysm (20 & 25+ levels, and shiny new equipment) Vael is still not a trivial fight.
 * Razorgore becomes difficult for a different reason with a high level group. He has less than 500,000 HP (about what most heroic WOTLK 5-man bosses have and what Cataclysm 5-man trash mobs have), and is easy to kill, but many groups will try to kill him before destroying the eggs, leading to a wipe when he casts an instant-death spell on the entire raid upon dying. This serves as proof that players can't simply zerg their way though old raids.
 * Every boss in the early instances of cataclsym will kill you in one hit if you don't obey their mechanics, this is meant to re-temper players after wrath content was made easy by the accessability of gear.
 * Corla is probably the best example, as if you don't manage the stacking debuff, either one of your party members will turn into a drakonid and get mind controlled, or one of the cultists will, leading to a wipe.
 * In a similar fashion, Guild Wars features Wake Up Call Missions. Probably the most Egregious example is Zen Daijun from Factions. Minister Cho's estate was virtually a tutorial. When you get to Zen Daijun and face a whole HORDE of the Afflicted AND that horrible Miasma which spreads degenerations around your entire party (particularly bad if you're using henchmen, who don't know well enough to not stand in close formation and keep reinfecting each other) AND you have to bodyguard 2 (admittedly very high level) NPCs... prepare to die.
 * Caruban, the very first boss of Legend of Legaia, is actually a pretty decent challenge, as it has more than enough attack power to bring either of your first two characters to their knees in a single combo attack. If that wasn't bad enough, it also has a flame breath attack that can easily wipe half of Noa's HP and as much as a third of Vahn's.
 * In the sequel, Elfin serves as a combination of this and Beef Gate. She is designed to be easy enough if you are at least level 9 and have four art blocks, but difficult to impossible otherwise.
 * Amorphes from Avalon Code will force you to see the monster description, or you won't be able to beat him.
 * In City of Heroes, Frostfire, the first elite boss players have the opportunity to face, fits this trope perfetly. He's fairly trivial compared to most later elite bosses, let alone archvillains, but he's much harder than anything new players have seen before him. On top of that, many veteran players avoid the Hollows, denying new players a source of advice.
 * Part of what gives Frostfire his infamy is that most players (particularly new players) go about the fight all wrong. Generally, players running through the Hollows content try to put together a full team of 8 to take him down. This means that the final room containing the man himself also contains 20-30 mooks, and the icy terrain makes pulling them away nearly impossible. With a team of two or three, however, the final room is much emptier, and it's far easier to grab him alone.
 * Vampire: The Masquerade Redemption (a Videogame/Diablo clone set in the Old World of Darkness) had Mercurio, a Cappadocian librarian who was just a liiiittle bit overpowered, as he would chain-cast an area of effect spell that had good chances to affect both of your characters, deal major damage and induce a frenzy (i.e. you lose control of the character, who just starts spamming powers and attacks at random). Compounded by the fact that, at this point in the game, you have likely not spent XP to upgrade your vampiric powers... He was, however, tweaked down in a patch and is now quite beatable.
 * Vampire: the Masquerade - Bloodlines features Bishop Vick, who you can fight very early on. Most of your boss fights up to now have been with melee fighters in areas with lots of cover to hide or disappear behind. Vick, on the other hand, is incredibly fast, wields a shotgun that he's very good with, and even if you run behind the scant cover, he can see through your invisibility power. He's a pushover if you wait to fight him until you've become more powerful, but he will absolutely shred a low-level character, and there's no warning given that he's going to be so hard.
 * The Hellhound at the end of Act I of The Witcher is one of these. The player can be easily stunned by it while it's pack of barghests chomp away at leisure, even with strong Group attack skills. One good blast of Aard can set up a one-shot kill, a feat impossible with later bosses. The battle also shows that some allies can be unkillable in battle. It also shows just how helpful alchemy is, as the right oils and potions can make the boss a walk in the park.
 * Persona 4 has Shadow Yukiko at the end of the first dungeon. The game makes it hard enough to keep up with her damage output, especially her multi-target fire attack (to which one of your characters is guaranteed to be weak) on her own. You can make her minion skip half of its turns if you have a good understanding of the battle system, but if you don't, between its damage, buffs, healing, and status ailments... good luck.
 * In Choral Castle, Arietta the Wild and her friends from Tales of the Abyss. As most Tales games go, team boss fights are difficult, and as the first one in Abyss, she surely gave a wake up. While her Liger and Birdie (name escapes me) pummel you, Gloomietta buffs up their attack and defense along with nasty dark and light spells. As a pain as it was, it does teach you the wonders of Free-Run.
 * For those playing Unknown difficulty, the Rhinossus counts. It is the very first enemy of the game, which players can easily beat on their first playthrough...but on Unknown, it can take upwards of 10 minutes for the party to beat it to death, and that's assuming New Game Plus benefits. This establishes very quickly just what kind of difficulty Unknown is.
 * The Tales of Vesperia fandom has nicknamed Gattuso, a large wolf and the third boss of the game, the "noob killer." It attacks quickly and ruthlessly, tosses the party around the battlefield like rag dolls, can poison with one of its attacks, and can charge from one end of the field to the other in two seconds flat. To add insult to injury, this was the boss of the 360 version's demo, meaning its brutality was several people's first experience with the game. Also, right after the battle, Adorably Precocious Child Karol goes "What the heck? It barely put up a fight!", infuriating many new players.
 * Zagi can also be this on Very Hard and Unknown. This gives you a taste of what the harder bosses in the game are like. It's ridiculous to level up in the castle without using equipment from the last game you played, meaning that you will most likely not gain very many levels, if any, before the boss battle. For a first boss, Zagi is tough, being fast, with annoying artes, and with Yuri being alone... until miss Princess steps in to help. She can heal, but, her AI is infuriating for most players, with her tendency to run up and attack, only healing when someone is about to die if they take one more hit. In higher difficulties, her running up to attack = instant death to the Princess. She's also slow as hell, so don't expect her to be able to get away from Zagi if he chases her. This battle teaches you how to "hit and run", and use Free Run though.
 * The first boss in Shin Megami Tensei: Devil Survivor, the first real fight with the Wendigo. The first time you see him, Amane is there and makes short work of him. The second time... well, let's put it this way; according to the Death Clock and Laplace Mail, if nothing changes, he's supposed to wipe out the entire party... and they weren't kidding. Take some time to get prepared before you face him, or you'll regret it.
 * Bishamon, one of the Four Devas, can also count. Not only is his fight the second with Rangda enemies (which Repel Physical, making Atsuro and Izuna completely useless), his Hassohappa (which can deal 1000+ damage to the entire party) makes it almost impossible to approach him unless you at least Null Phys. Not to mention he has (respawning) allies that can heal his massive HP stores (making Hassohappa hit worse). While most battles so far were almost all affairs where you mostly attack and exploit weaknesses, this one puts emphasis on defense using passive abilities.
 * The fight against Beldr, in addition to being That One Boss, is the first "Bel" enemy you face and warns you that the others will also require specialized tactics to beat.
 * The first battle against other tamers teaches players the value of AUTO skills.
 * Mabinogi uses this. Being an MMORPG, which boss it is depends on how you play:
 * If you try to take Alby Dungeon Normal, you'll face the Giant Spider. While the enemies before this generally do single-digit damage even to raw newbies, the Giant Spider can kill you in two or three hits if you're not familiar with defensive tatics -- an attribute which will be shared by both bosses and mooks going forward. It's also a Flunkyhat drain at least half of your SP each time the card activates, and at least a third of your HP, making healing yourself or even getting any skills in next to impossible, unless you have Roxis use a skill that removes some of the timecards.
 * Dragon Age 's first "Red" (Boss) enemy is the Ogre. Up until this point, you've had some tough, but winnable battles, mostly against mooks, where some relatively simple tactics will generally win the fight. The Ogre, though. . . hooh boy. ..
 * The entrance to the tower is a Wake Up Call Level, too. You're running headlong into a trap fanged by a fireball-using Emissary and several archers. That teaches you to get in smart, fast, and take down the enemy before you get taken down.
 * The first boss in Awakening, The Withered, gives you a taste of being on the receiving end of the new high end talents available in the expansion. The moment you see all the damage dealt to him being reduced to zero thanks to "Carapace" is the moment you realize that the new abilities are not to be taken lightly.
 * Barkley Shut Up and Jam Gaiden has the Ghost Dad. The first few bosses in the game were relatively easy to dispatch, and this boss, being a spectral Bill Cosby, doesn't seem like it would be any different until you actually fight it. Among his tricks are lowering your speed (giving him more turns), increasing his own power (which is already fairly high to begin with), and worst of all, inflicting the whole party with multiple random status ailments all at once. And he uses that last attack quite liberally and it's even worse considering that there isn't a whole lot you can do about status ailments this early in the game. If you don't come into the fight prepared, he will wipe the floor with you.
 * Vagrant Story doesn't feature a single easy boss, but at least the first few don't require much skill beyond picking the right weapon type and not standing right in front of them when they try to hit you. Then, after around 3 hours of gameplay, you finally escape the first dungeon and reach the above-ground part of the city. Including the first human boss - a priest general - two screens away from the dungeon gate. For the first time, you're really going to need those armor spells, reaction abilities and risk-reducing potions.
 * You can breeze through the first half on Atelier Annie quite easily by buying your raw materials instead of gathering and by ignoring jobs with attribute requirements. But then assignment 5 has you fighting a not-insignificant monster. If you've neglected to raise your exploration level, you're in trouble two ways. First, the monster will clobber you and you'll need either some level grinding or bomb items to win. Second, just beating him isn't enough for the Gold Medal- to get that, you must grind for a certain rare drop, trade it to an NPC for a specific weapon, find an item that makes a particular Supplement (which isn't even available unless your exploration level is at least 20), and then enchant the weapon with the right attribute using the supplement. Not too hard if you know it's coming, but if you don't, kiss the Golden Ending goodbye.
 * The first two Shining Force games have some rather nasty first bosses.
 * The first game has the Marionette, which can recover hit points, has Freeze 3 (which can kill up to five units at once), and has more than enough MP to wipe your party out. You need to coordinate your units, or else he'll destroy your troops and be back up to full health before back-up can even get there. If you promote your units too early, this boss is even more difficult.
 * Mishaela, much later in the game, serves a similar purpose with her stupidly-large-area Bolt 2.
 * The second game has the Kraken, which has eight strong legs, a pair of even stronger arms that can strike units at a distance, and the head itself, which has high HP and a bubble attack that ignores defense. To make matters worse, you have limited movement and of the two (three if you promoted Kiwi) flying units you can have at this point, Peter is the only one who can consistently and immediately do some damage.
 * The boss after that is Taros, an iron giant that can only be harmed by Bowie if he's He can take a beating, deliver heavy damage to one unit with regular attacks or multiple targets with Bolt spells, and like every other boss, gets two turns to attack.
 * Before Shining Force, there was Shining in The Darkness, whose hard-hitting Kaiser Krab gave players their first real challenge.
 * Breath of Fire IV has Ymechaf, which is encountered roughly a quarter through the game. His attacks are fairly powerful, but his defense is sky high. In short, the boss is the game's way of telling you "You're gonna wanna learn some of that combo magic."
 * The Etrian Odyssey series contains many good examples of this, such as a F.O.E. on the very first floor of the game that will utterly destroy most mid-leveled parties.
 * Although unfittingly placed, the endgame of can be considered a wake up call because anything but a well-planned team of high leveled, well-geared characters will get utterly slaughtered where as the rest of the game presented (relatively) little trouble.
 * Secret of Evermore has two bosses that will make you realize that yes, you do need to learn a bit more about this game's combat system if you want to reach the ending. The first is Salabog, the massive sea serpent in Prehistoria. He has 2000 HP (compare to the previous boss's 600), he spawns mooks that can hurt you by touching you (they're made of FIRE), and he only emerges to spring an attack on you and to make more mooks. If you haven't learned how to use charged spear attacks, or haven't leveled your spear up enough to throw it at all, you're gonna be in for a long, painful, and ultimately futile battle.
 * The second is the Verminator, one of the later bosses of the medieval times world. This guy sits on a pile of crates, and will never come down, making him the first boss that you encounter which cannot be affected by regular attacks. He relentlessly uses status effect spells and attack spells on you, and, again, if you're no good with spear throwing, you're gonna die, since you'll run out of attack spells well before you get anywhere near killing him. You need to not only be very good with your spear, but also good with alchemy so you can cure the status afflictions he causes and protect against his attack spells. If, through some miracle, you've made it this far without learning about charged attacks, you're never going to win. The fact that he's placed at the end of the forest maze, and the fact that the inn and save point are so easily missed, add to the aggravation.
 * Number 9 in Parasite Eve 2 serves as a wake up call boss. He has a paralyzing attack and a one hit kill attack. He also has massive amounts of HP to boot. If the player doesn't realize to use the electrical boxes on him, fails to find the MP5 or grenade launcher, there's not a lot of hope to beat him.
 * Persona 3 gives us the Change Relic around 20% into the game. Up until now, any enemy that isn't easily pummeled to death by exploiting Elemental Rock-Paper-Scissors is handled with little trouble by exploiting the party heal of the Cadenza spell. Change Relic has no elemental weakness, and its wind magic can hit every party member for a good chunk of HP, or just hit one target for a potential One-Hit Kill. Then there's Poison Mist, which poisons your entire party, putting you on a very fast clock if it hits early. This is the point at which savvy players realize that sometimes, there's no substitute for good old-fashioned Level Grinding.
 * Hard as that is, though, Change Relic is actually a blessing in disguise. There's a checkpoint immediately before it which takes you back to dungeon lobby, so dying loses you five minutes of gameplay, tops. If you're stubborn and don't get the message there, however, the game punishes you with Emperor and Empress shortly thereafter. They're not especially difficult if you're adequately leveled and prepared, but they'll destroy you if you're not. And there's a series of lengthy cutscenes between them and the most recent save point.
 * And then there's Hierophant. It has a multi target attack that put your party members in Fear status. Fear causes them to skip turns, makes all physical attacks against them criticals, and makes them vulnerable to a One-Hit Kill from Ghostly Wail. He also attacks with Lightning magic, which one party member is weak against. Me Patra Gems help with the Fear effect, but it's still very possible to die simply because the Random Number God decided to be a dick.
 * The Rampage Drive in is among the first four bosses in the game, and it is totally immune to physical attacks and also resists fire. To make matters worse, it has a very powerful physical attack that can wipe you out in one shot even if you're at full health, as well as an electric spell that hits the whole party (and one of the three starting party members is very susceptible to electricity).
 * In Resonance of Fate, the first real boss "Tar Man" Will destroy your team repeatedly, until you pretty much master the combat system and learn that not every move needs to be a "Hero Action." Even then, he has a lot of armor and requires multiple death-defying passes to take down. To top it off he will regenerate his health (but not his armor, thankfully) if you don't kill him fast enough.
 * The Marid King in Last Scenario is something of a rude awakening if you thought the game had been tricky up to that point. He serves to teach you that a) status effects in this game are pure evil and b) stealing from random encounters is not a waste of time. If you didn't grab an Alarm Bell or three from the kelpies, your entire party is going to wind up asleep. And, irritatingly, you can't backtrack from that dungeon to pick up more supplies. (You did keep a save file from before you left, right?)
 * Cla Dun: This is an RPG! doesn't have very many boss encounters, and most enemies can be dealt with through basic attacks. However, when you reach the last floor of the Monster House, you'll have to deal with a fire knight, who has an incredibly powerful Flaming Sword attack and has a shield that greatly reduces damage from frontal attacks. If you haven't been making good use of your Magic Circles and Upgrade Artifacts, you're going to get beaten down repeatedly, even with high-leveled characters serving as your support/shields.
 * In Inazuma Eleven things will go very smoothly up until you meet Mikage Sennō Junior High (Brain Washing Junior High in the english anime dub). Unlike your previous opponents, MSJH have much better defensive and ball-keeping stats than your vanilla footballers, and their Killer Techniques, especially those used to steal and keep the ball are much stronger than most of your team's. It doesn't help that they won't lose any TP during the first half, which basically guarantees that they'll have drained poor Raimon Eleven's energies, unless the player brings enough items to sustain the characters. Worst of all, MSJH have the tendency to play very defensively after scoring a goal (something that is reflected in an episode of the anime).
 * Dragon Quest games can be hard, and often pack a Wake-Up-Call Boss to let you know that.
 * Dragon Quest VII has Deathpal. He has tons of HP, gets two turns per round, an blind you, has a powered-up attack and none of your magic works!!
 * Dragon Quest VIII has Geyzer who is pretty tough for a first boss, but Don Mole has tons of HP, can call for backup, has an area-of-effect attack, and can confuse the entire party.
 * Dragon Quest IX has the Wight Knight. Did you recruit any allies at Patty's Place beforehand?
 * In Dungeon Fighter Online the lightning Knoll is the first boss that legitimately can give you trouble. It's the first boss that posses powerful ranged attacks and it's moves can hit for a ton of damage. They also usually multihit, resulting in you failing a quest. Course he's easy relative to the later bosses.
 * In Golden Sun: The Lost Age, Badass Normal pirate Briggs is definitely this. He comes after you with two buddies for support, hits like a truck, uses both damage and recovery items, and will call more buddies if you take down the ones he starts with. Worst of all? It's way too easy to accidentally reach him far earlier in the game than you're supposed to, underleveled and underequipped.
 * Dark Dawn drops the Stealth Scouts on you in the Konpa Caverns, who also like damage/recovery items, team tactics, and add Standard Status Ailments (Stun Shuriken) and Mana Burn (Psy Grenades) to the menu. The last of these is a real terror unless you know how to exploit Djinn (and have collected them all!) or spam recovery items of your own, since it ruins the possibility of healing Psynergy.
 * The original Golden Sun was possibly the worst offender of this in the series. The player had likely fought a few bosses by the time they reach the Mercury Lighthouse. The bosses before it being a trio of bandits and (possibly) a possessed tree. Neither were exceptionally difficult. And then they must fight one of the games main antagonists, who has a brutal physical attack, and plenty of hit all Psynergy while you have no group heal spells or items. Oh yeah, and your recently acquired healer can die in one bad hit from him thanks to her elemental attribute. Have fun!
 * Qudamah the Jackal can be this for Two Worlds II players, as he's very easy to run into by accident while exploring and completing quests in the first act of the game and is considerably stronger than anything else you fought so far. The quest leading up to him is extra deceptive in that it makes you go after a bunch of weak Varns in a mine, lulling you in a false sense of security only to then throw this unholy canine-faced terror at you without warning. Hope you didn't saviring weapon such as Rynex-R's Thunder Sword.
 * The early levels in Bangai-O have fairly simple bosses that shouldn't give you too much trouble (especially since Sabu is fought in the first four). Then, you get to 86, level 8's boss. She uses reflective lasers like Mami's, forcing you to use EX attacks and keep your distance more effectively in battle.
 * The Rusted Dragon in Hellsinker is much harder than the bosses of the first three stages. Blowing off its parts, which normally weakens bosses, only serves to make it harder and more evasive. However, if the player is doing horribly, you can actually skip the entire boss fight.
 * The hardest of the first four bosses in Giga Wing is the battleship. Two people have this as their FIRST stage in the rotating stage lineup.
 * The Capra Demon in Dark Souls is the first taste of just how unforgiving the game is to the player.
 * In the Dark Spire, most of the early bosses range from only a bit harder than normal fights to actually easier than normal fights. Then you hit the first boss with a breath weapon. It can nearly OHKO your party. Then the second one CAN OHKO most of your party and the third can OHKO all of it. All of these are designed to teach you the importance of the Cast Quickly command. If you don't use it, you will die.
 * Monster Girl Quest has the Queen Harpy. Up until now, you could get by with "attack-heal" strategy. The Queen Harpy shows you that attacking without paying attention will get you stomped flat from that point on by having an insta-death Counter Attack. It drives home that you need to watch what the enemy is doing instead of attacking continuously.
 * Magical Starsign has the first encounter with Master Chard. It's a long fight, so you'll have to get used to party members gaining and losing advantage based on the planet orbits and day/night cycle; next, he has a devastating all-party hit which is telegraphed several turns in advance, teaching you how to prepare for and recover from battle-defining boss abilities; and his HP pool is so massive that you are almost guaranteed to run out of MP, forcing the player to appreciate strategic item use, which is a must when it comes to surviving difficult encounters in this game.
 * Cerberus from Kingdom Hearts. The bosses before him are either simple enough, or difficult, but not necessary to win. Cerberus marks the point where bosses stop going easy on the player, sporting nasty attacks (particularly snapping at an attacking player), and more HP then anything else at that point. It's especially nasty if the player follows the difficulty levels of the worlds, since he or she won't have the Cure spell at this point.

Simulation Game

 * To some extent, the enemy ace squadron encountered in the player's first trip to the Round Table in Ace Combat Zero counts. They're the first major aerial enemies you face and can be quite difficult to take down in starter fighters. With more advanced birds, they are a good deal less tedious. Most of the ace squadrons across the series, in fact, qualify.
 * The first three missions in Mechwarrior 3 are relatively easy with the toughest enemy you face being a suit identical to yours, that being a 55-ton Bushwhacker. Then mission 4 comes up and pits you against the first heavy mech of the game, a 70-ton Orion. Due to the fact that the Bushwhacker is not really a great mech and the rather weak weaponry you have this early in the game, if you have not mastered the art of "legging" (shooting out the leg of a mech to take it down quickly), the Orion will most likely tear you apart.
 * Armored Core For Answer has White Glint, who is notorious for chewing through newbies to the game, using its overwhelming speed to dodge all of their attacks.

Sports Game

 * The Dallas Mavericks and Minnesota Timberwolves, the FIRST TWO TEAMS YOU FACE in NBA Jam, qualify as these. In both the original and the tournament edition, the Mavericks are one of the fastest and most efficient shooting teams in the game; Jamal Mashburn (or Mike Iuzzolino) can easily make players' lives a living hell. The T'Wolves can slip up a careless player in the Tournament Edition due to the fact that Christian Laettner and Chuck Person sink 90% of their shots to end a quarter.
 * When you get to the Charlotte Hornets, the game pretty much tells you: "welcome to Hell." Larry Johnson and Alonzo Mourning are both Lightning Bruisers who can also shoot the lights out, while Hersey Hawkins cannot be discounted thanks to his own speed and shooting ability.

Third Person Shooter

 * Resident Evil 4 features a wicked and terrifying early encounter with the chainsaw-wielding Dr. Salvador. Aside from being Nightmare Fuel, this nasty enemy probably killed 90% of gamers the first time they set foot into the opening village. Players can avoid this encounter by passing up the shotgun during the opening shootout, which given you have only a weak pistol and a couple of grenades is a sort of wake up call in itself. Of course, new players will have no idea that going into that house will result in them getting access to the shotgun...