Boss Arena Idiocy



""If I must use a monster too tough for the Hero's weaponry to hurt, I will never put it in a room with weapons, devices or explosives which CAN hurt it.""

- All the Tropes Additional Evil Overlord Vows

""You can't win! This suit is impervious to everything, save for conveniently placed lava crystals.""

- Killbane during the final battle of Saints Row The Third

A trope most common in video games where a boss would be unstoppable if it weren't for something unique to its arena.

Often overlaps with the Puzzle Boss, but sometimes it's so obvious the game doesn't intend it to be a puzzle. The Ring Out Boss is almost always based around a form of this, where the boss has to be killed by being pushed back into obstacles in the arena.

A Sub-Trope of Convenient Weakness Placement. Compare Tennis Boss and Tactical Suicide Boss, which pertains to the boss' moves rather than the arena.


 * Super Mario Bros.:
 * Practically every fight against Bowser in platformers is like this. Most blatant example is in Super Mario 64, where Bowser has learned to recover from the bottomless pits/lava that usually defeated him in the past and would be completely invincible if it weren't for the floating mines surrounding his arena that Mario has to go suicidally out of his way to be hurt by.
 * Super Mario Bros 3 has Bowser jumping on a fragile floor.
 * Happens quite a bit with the other bosses in the Mario series. For example, the electric fence in the arena where you fight Topmaniac in Super Mario Galaxy, lots of examples in the final Bowser battle (plants and those blue panels with lava underneath), etc.
 * In the Wario Land spinoff series, a certain few bosses have lava around the arena they need to be smashed into, and another has water on both sides of the arena for no real reason than the boss to be knocked back into.
 * Red-Brief J from Wario World would be completely invincible if it weren't for the lava under his arena.
 * The mirror-located Cataquacks, Wiggler and Bowser in Super Mario Sunshine.
 * In the the first Super Mario Bros, Bowser (and each of the fakes) stands on a bridge. On the other side of the bridge is an axe. If Mario can pass Bowser and get the axe, the bridge and Bowser fall and you win. Classic.
 * Lampshaded in Brawl in the Family, as seen in the picture above.
 * Even worse in New Super Mario Bros where the fight is the same, but the axe is replaced by a large button with a skull on it.
 * Mario & Luigi: Bowser's Inside Story; Second Giant Bowser boss. You have to knock it into the water.
 * Inverted in the very next Giant Bowser fight where you, as Bowser, have to beat the enemy before you get led onto a collapsing bridge over a bottomless pit (which gives you an instant Game Over if you reach it).
 * In the Western Super Mario Bros. 2, Wart can only be killed by having vegetables thrown in his mouth. He has a machine in his throne room that shoots vegetables. He also opens his mouth a lot. Wart is not very smart. And apparently there's a reason. Wart stole the Nightmare Machine and reprogrammed it to bolster his army. Problem is, the thing has a mind of its own and it decides to help kill Wart.
 * King Totomesu, the first boss of Super Mario Land, has a boss stage that looks just like Bowser's, and can be defeated in the same manner - either run under him when he jumps so that you can hit the button behind him, or pelt him with five Superballs.
 * The tradition is continued in Super Mario 3D Land. Like New Super Mario Bros, it's a button, only this time it has his insignia on it!
 * Something:
 * The boss of the Chateau du Vent has plenty of throw blocks in its arena. If these blocks were replaced with an ordinary platform, the boss fight would be impossible.
 * The boss of Chateau de la Terre still has the throw block problem, but there's only three throw blocks in said arena.
 * The Pain from Metal Gear Solid 3: Snake Eater. He's a guy who's covered in bees. The only place where you can't be hurt by his insect 'brothers' (though all worker bees are females without the reproductive capabilities of the queen) is in water. So where does The Pain, in his infinite wisdom, choose to ambush you? On a rock in a lake, of course! How could that possibly backfire?
 * In the original Metal Gear Solid, Liquid Snake can't be defeated through normal means and you don't have access to weapons while fighting him. Conveniently, despite having hours to prepare for the battle, he chose to stage the fight on top of a Metal Gear with nothing to prevent him falling off. Not that falling off stops him for long.
 * Zelda has plenty of examples.
 * The Legend of Zelda Oracle Games
 * Seasons: The Dodongo fight is like the original, but you need to use the Power Bracelet to throw him into the spikes after he swallows the bomb. Why are there spikes there? There's also the random giant metal spike ball in the area of the fifth boss, Digdogger. Good thing you got those Magnetic Gloves beforehand, and no, the spike ball doesn't reappear later. Both Agahnim and the Poe Sisters would have fared better if they didn't fight in areas with torches.
 * Ages: Smog adverts this by making you play a 'game', changing the arena to try to get his separate parts together. The game, being more puzzle-orintated than Seasons, avoids this.
 * The Legend of Zelda Twilight Princess:
 * The game's Gohma incarnation fights you in an arena filled with giant, hammer wielding statues, the only way to kill it and the only such devices in the game.
 * Dangoro, the Goron miniboss from Death Mountain, is also this.
 * The boss of the Arbiter's Grounds chooses to fight you in a circular room that conveniently has grooves spiraling up it, allowing Link to ride up on the disk item he has found and attack.
 * Fraaz from Spirit Tracks takes a rather different approach; upon noticing that Link has been using the two torches in his chamber to damage him, he simply reaches over and smashes them apart. And then he starts using attacks that can be used as replacements for the torches to damage him, making it only a little harder than before.
 * In The Legend of Zelda the Wind Waker, fighting the boss Jalhalla involves hitting him with light from holes in the ceiling and throwing him into spiked pillars.
 * Gohma is invulnerable to grapple and sword attacks, because she is shielded by a thick layer of armour. Handily, the boss fight takes place in a cavern with a weak ceiling and a dragon's tail poking through it. Putting a little bit of weight on the tail causes part of the roof to crash down, destroying her armour.
 * Sonic Unleashed:
 * The boss Dark Gaia Phoenix fights you in an area with the game's first throw-ready water barrels, which are necessary to hurt it. Said barrels continue to show up solely in areas where fire-protected enemies attack you.
 * In Sonic Adventure, Amy's story has her pursued by a robot, Zero, who can be stunned by her hammer but never actually destroyed, and if you hit it enough times, it becomes invincible. However, in Amy's only Boss Battle, the arena is surrounded by nodes between which electricity constantly arcs. Knocking Zero into the electricity stuns it and exposes a vulnerable button which may be hit by Amy, thus damaging it.
 * Chaos 6 from the same game would probably wear down Sonic and Knuckles if those robots didn't come into play; stunning the robots then causing Chaos to ingest them freezes him, thus allowing attacks to actually hurt him. In one version of the battle, Eggman himself dispenses the robots, then complains when you're able to use the robots against Chaos. And, when you damage Chaos/Eggman after that display of idiocy, his reaction is a memorable "No way, I can't believe this!". This man has an IQ of 300.
 * And let's not forget the very first game; the Green Hill Zone boss would be unbeatable if he didn't decide to strike in a screen with floating platforms.
 * And ditto for the Star Light Zone boss, which would be impossible to reach or harm if it didn't drop its bombs.
 * The Biolizard would be a lot more difficult to kill (not that it already isn't), if it didn't produce a load of pink bubbles, that could be used to reach its life-support system. Stopping to catch its breath is more forgivable, since if it didn't, it would, well, die.
 * Easily the biggest example from the Mega Drive era would be the Sandopolis miniboss from Sonic and Knuckles, which is completely invincible to the heroes' attacks but definitely not invincible to the pit of quicksand you can lead or knock it into.
 * From the same game, the "normal" boss of Death Egg (before the final boss sequence) automatically deflects all attacks and drops robotic minions on you, which are the only things that can damage it. The only reason you can even do so is because he picked a room that happens to let you flip the gravity.
 * In the boss fight for the Ice Mountain Zone from Sonic Advance, Robotnik is moving along the top of the arena, just barely out of your reach. You're under water for the duration of the fight, so if you stay under for too long, you'll drown. Robotnik would've been impossible to defeat if it weren't for him sending icebergs down your way, which you can jump onto and use to both damage him and get a breath of fresh air.
 * Shadow the Hedgehog isn't immune either. Dr. Eggman's "latest and greatest invention" includes buttons that couldn't possibly benefit him, most notably the ones that trigger Shadow Fever. It may have been used in order to power up those Shadow androids he made, but he really should have had the foresight to disable that feature when the real Shadow showed up.
 * Several times in Resident Evil.
 * The T-078 Tyrant in Resident Evil Code Veronica has a distinct advantage in the enclosed space of the plane, only to be defeated thanks to a lone crate in the cargo hold.
 * In Resident Evil 4 Salazar's Right Hand (i.e. one of his two main servants) has several liquid nitrogen tanks that slow him down and make him vulnerable in his area, and when you fight two El Gigantes there's a lava trap you can use to kill one, but it technically isn't required in any way.
 * In Resident Evil 5, the second boss battle against Wesker. It's oddly convenient that he can't see you in the dark, and you just so happen to be fighting him in an arena with easily-located light switches!
 * God of War:
 * Pandora's Guardian, the giant, armored, demonic, fire-breathing zombie minotaur, fights Kratos in a narrow corridor with some sort of ballista mechanism at one end of it; Kratos can use the ballista bolts to chip away at its armor, and eventually defeats it by impaling it on the door at the other end of the room.
 * Clotho fights in an arena filled with deactivated traps that aren't at all suited for hurting someone the size of a normal human. Kratos, of course, uses them to kill her in an elaborate puzzle boss battle.
 * Perseus' preferred tactic is to use his helm of invisibility, then either sneak attack Kratos with his sword or take potshots with his sling. Unfortunately for him, he is forced to fight Kratos in a room with a shallow pool of water, meaning you can use the ripples and splashes to help figure out where he is.
 * In the third game Heracles is wearing armor made from the pelt of the Nemean Lion, whose golden fur is nearly impregnable. Heracles by extension would also be invincible, were it not for his tendency to stop, bellow loudly, and drop his guard with a bum rush long enough for Kratos to counter it and slam him into one of the walls of spikes set up around the arena that keeps him in place long enough for Kratos to remove his armor.
 * Kirby and the Amazing Mirror:
 * The Mega Titan is Nigh Invulnerable unless he gets knocked into the convenient electrical barriers on either side of his boss arena. The Spark ability works, though.
 * As does the Beam ability. If you're adequately prepared, he's actually one of the easier bosses in the game.
 * In Psi Ops the Mindgate Conspiracy, Marlena Kessler fights you in a room full of liquid nitrogen canisters. This is rare as there's an actual reason for her to fight you there; her fusion cannon wasn't exactly portable. Although the infinitely replenishing liquid nitrogen canisters aren't so excusable. Notably, it's also possible to fight her without the cannisters after you destroy the cannons (though it's insanely difficult).
 * Iji:
 * It starts with this as early as the first boss. The turrets that pop up on occasion do a lot of damage to the boss, with the added incentive that you want to deal with them quickly to prevent them from shooting you. The Komato Sentinel would probably wipe the floor with Iji if not for the conveniently located electrified pads she can knock it into, and the initial form of Iosa The Invincible is very hard to kill without using the lasers in her chamber. Enforced because Iji has an experience system that lets you build combat abilities or more stealth/exploration oriented skills. Thus, to prevent players taking a noncombative route from getting stonewalled, nearly every boss is a Puzzle Boss.
 * Defeating Proxima, the Sentinel without using the electropads actually gives you a reward. It's not too hard provided you brought enough ammo. Iji comments on it by saying "Guess it pays to be prepared".
 * Lampshaded in You Have to Burn The Rope.
 * Crash Bandicoot:
 * (the first one) Ripper Roo is invincible. The only way to harm him is to jump on TNT that's moving down the river between the two platforms and hope that the explosion hurts Ripper Roo. Same thing happens in the second game, but this time, he's a Tactical Suicide Boss, the whole thing is just surviving long enough for him to kill himself.
 * In Crash Bandicoot 2, Tiny is invincible. The only way to harm him is to hop around on the platforms, avoiding him, until they blink red. Once they do, hop onto a non-blinking platform and hope that Tiny lands on a blinking platform and falls, hurting him.
 * In Crash Bandicoot 3, N. Tropy is... not invincible. However, he has you at the far end of the arena from him, and thus you can't do a thing, not having a distance attack. Until he switches the platforms to create a direct trail to him... and then takes that moment to catch his breath and stop attacking you.
 * Almost all boss battles in Crash of the Titans are only winnable because the bad guys are considerate enough to populate the arena with weaker Titans, so you can capture something capable of hurting the main boss.
 * In Crash Mind Over Mutant, the boss fight against Evil Crunch and N. Brio has the boss in a decrepit weapons factory - next to a conveyor belt steadily supplying TNT Crates, which are the only thing capable of blowing up Crunch's cannons. Then, later on, when facing a mutated Cortex, the boss is defeated by taking control of Cortex and spinning a screw out of the ground then body slamming the self-destruct switch for the Space Station the fight occurs on. The screw in the ground is only uncovered when Cortex's defenses and minions are defeated.
 * In the first Sly Cooper game, Muggshot's arena is filled with person-sized grounded light bulbs. To defeat the boss, you have to reflect light onto the light bulbs (thus making them completely impractical for non-combat use), and lighting them all hurts Muggshot and melts his guns, despite not hurting your character. There's no attempt whatsoever to explain why Muggshot keeps these things in his office.
 * Being a game composed entirely of boss battles, Shadow of the Colossus naturally employs this trope.
 * A memorable example is the eighth Colossus (Kuromori, the lizard), who you fight in a ruined Colosseum. He has incredibly powerful lightning attacks, and there is no way to damage him at first. If he stood still, he would be invincible. But, if you aggravate him and hide, you can get him to climb the walls to try to hunt you, at which point you can shoot him to make him fall down, leaving him vulnerable.
 * Both of the "dogs", smaller and faster Colossi that chase you around, are beaten this way. The first is said to be afraid of fire (the only one that is) and lives in an abandoned temple... that has torches around (the only place that has them, mind) so you can scare him with them to push him off a ledge and destroy the armour. The second chases you around as you bait it into knocking over pillars to you can hop onto a ledge, which it crashes into. The final pillars cause the ceiling to collapse onto it, destroying that armour as well. Had they traded locations at least the first one would have been impossible.
 * Also memorable is the 16th Colossus, Malus. His lightning attack is even more powerful and has strong knockback. Although he holds the high ground in his arena, the arena is also filled with defensive walls and tunnels you can hide in, to approach his blind spot.
 * Partly justified as Malus can't move and can't destroy either the walls or the tunnels. He tries.
 * Most of the boss battles in Donkey Kong 64 have a random, convenient, COMPLETELY unnecessary exploding barrel in the middle of the room that, if removed, would make even the first boss impossible to defeat.
 * Mega Man and Bass' Burner Man decides to fight the titular heroes in an arena blocked off by two pits of spikes (which usually are a One-Hit Kill, but will simply damage Burner Man for about 1/4 his total health). Although Burner Man himself is at least smart enough to avoid the pits while he's dashing around and trying to hit you, if the player brought along Cold Wall (Burner Man's Kryptonite Factor), and slides it into him...
 * Cut Man, from the very first Mega Man game, is weak against Guts Man's power. Guts Man's power is simply being very, very strong. Mega Man can use this strength to lift giant brick blocks and throw them away or at enemies. And for a literal case of Elemental Rock-Paper-Scissors, guess who's got a few brick blocks in his arena for no particular reason?
 * BlastMan in Mega Man Battle Network 6 has two metal cubes on the field when you fight him. Those become important, when he uses his strongest attack, sending a wave of fire from either up, down or side and forcing you to hide behind the cube. Later, when you re-match him, if you play Falzar version, you can suck in the cubes using Dust Cross, and fire them off at BlastMan for nice damage. Doing so will leave you defenseless when he uses his wave attack, though.
 * BubbleMan in Battle Network 3 subverts this. He spends the entire battle with a bubble shield, and behind a rock. The bubble shield will take one hit regardless of damage, the rock takes some time to destroy, and his attacks are designed to keep you busy.
 * In Super Metroid, Draygon's lair is surrounded by turrets that fire balls of plasma at intruders. A few missiles render them inoperable, however, leaving behind bare high-voltage circuitry that can be used to electrocute Draygon in four seconds flat. The boss can also be defeated the old-fashioned way with loads of missiles, but frying him is easier and considerably faster.
 * Batman: Arkham City:
 * It subverts this hard in the Mr. Freeze fight: Freeze didn't design his hijacked lair (an old GCPD forensics unit), but once you've used the environment to land a stealth attack on him he promptly alters it via his suit's mechanisms so you can't use that trick again. You need to find about seven different methods of weakening him.
 * However boss fight resembles this. One of his attacks is to roll into Batman: if done right, you can have him roll into the explosives set in the corners of the room and severely weaken him.
 * Quake has at least two of these. The first chapter boss is completely immune to all damage apart from two adjustable columns that can shoot lightning between them. The final boss is impervious to everything except a floaty teleporty doohickey. Neither of these unique architectural features can be found anywhere else in the game.
 * In Spyro 2, the boss Crush combines this with Tactical Suicide Boss. He fights you in an arena where using his giant club sends debris falling on him from the ceiling, the only thing that injures him. He has plenty of other attacks as well, but if you annoy him he'll keep using his club.
 * In Attack of the Rhynocs, Ripto is defeated by leading him into destroying the three statues throughout his throne room.
 * In Kingdom Hearts, you fight Hercules in an arena you've already used for dozens of battles. Every single time before and after, it was completely empty, just a flat ring. For the Hercules fight, it's filled with barrels that you need to get rid of the hero aura which makes him invincible. The barrels being provided may be justified by the fact that it's more of a friendly practice match than anything else and Hercules is giving Sora sporting chance. There is, however, no explanation for why a wooden barrel is able to weaken Hercules so much.
 * PS1/N64 Spider-Man:
 * The Beat'Em Up was chock full of such examples, but the most blatant is the penultimate boss fight of the game against the symbiote Carnage. As Spidey tells you, a symbiote is weak against fire and supersonic frequencies, so naturally the room you fight Carnage in has a massive sonic bubble in the middle (presumably built by Dr. Octopus as a failsafe against Carnage) for you to knock him in. Other such examples include the fight against Doc Ock (with convenient "disable forcefield" buttons lowered to the arena one-by-one) and the Rhino boss fight (with electric pistons for the Rhino to charge into and electrocute himself with). The sequel lampshaded this, even, with the final battle against Hyper Electro where, after you trick the pure energy final boss into zapping one of the several generators in the area, which sucks his energy away and makes him physical again so he can be attacked, Spidey quips "Man, you'd think a guy would learn after a while!", or with "Remember kids, good always wins because Evil Is Dumb!"
 * Also in the sequel, the second fight with Sandman (the first being impossible to win) takes place in a construction site, which seems logical until you spot the open plumbing.
 * The final boss of the Prince of Persia: Two Thrones, Vizier can manipulate matter telekinetically and at the first stage of the battle he tosses debris at you which is perfectly understandable. Then he makes debris revolve around the arena trying to run you over with them which is also perfectly understandable. Finally he soars high into the air where he would be completely unreachable for you... if it wasn't for the debris that he, completely unintentionally, of course, arranges as a contrived obstacle course.
 * Rayman 3 has the boss battle with Reflux. Reflux is a Knaaren. Knaaren are an invincible race -- seriously, you have to get through an entire cave of them, and none of your attacks do a thing. Avoiding them is the only option. So Reflux, apparently one of the most powerful Knaaren (never having been defeated before, according to the Knaaren leader) should be a Hopeless Boss Fight, shouldn't it? Nope. Reflux uses a staff as a weapon and you attack that to defeat him.
 * In the first Rayman Mr. Stone can't be hurt at all by your attacks, and even the smaller rock men are Invincible Minor Minions that stay down only for a few seconds. Unfortunately for him the arena features a tall idol tower that can be knocked over his head and smash him to bits.
 * Xena: Warrior Princess has at least 3 such bosses. The first one is a Cyclops blocking your way. You are at a high cliff and the guy reaches from below, grabs the ledge with one hand and uses the other to smash you if you try to bypass him (why he doesn't try to climb up the cliff is beyond me). All attacks against him are useless. The solution? Keep slashing the hand grabbing the ledge and he'll fall off the cliff. Idiotic indeed. The second one is an invincible (to swords and chakram) fire breathing giant dragon that can only be killed by dropping stalactites on it. Admittedly, said stalactites are not unique to this level, you do get to make use of them to bypass obstacles in LATER levels, but still... The final boss is also invincible and constantly charging at you, and the only solution is to lure it to charge at the supporting columns. When enough columns are smashed, the ceiling will collapse and kill the boss while you hide under an uncollapsed section (if you have enough sense to rush there, that is.)
 * The Medusa boss in Hercules can only be killed by running around and hide behind shields mounted on the wall to reflect its gaze.
 * In Devil May Cry, the battle with Nightmare. He first appears as a completely invulnerable pool of black goo which swallows Dante up if he touches it. Hitting the switches that surround the arena enough causes him to take on a more solid form which, while more dangerous, is also vulnerable after it attacks.
 * ID Software's original Commander Keen game:
 * The final vorticon is immune to blaster fire. Luckily, he hangs around in a small area directly below the game's only example of destructible terrain - a large concrete block suspended by a thin chain. Just don't ask how he got into that situation since he's too large to fit through any of the gaps in the walls around it...
 * The Vorticon Commander can be killed with blaster fire. It takes over 100 shots, but doing so nets you a few extra Teddy Bears that are otherwise blocked off by the fallen block.
 * The in Ico saw fit to decorate  with movable, mystical stone pillars that nullify . All it takes is for Ico to drag them around the room and hide behind them at regular intervals until he can get close enough to.
 * In Luigis Mansion, Boolossus is completely invulnerable to everything except being pulled by Luigi's vacuum attacks. Conveniently, the roof where you fight him inexplicably has a pair of stone unicorns..
 * Lampshaded in Portal: the only way you can defeat the rogue computer GLaDOS is by manipulating incoming rocket fire through portals to hit her. Though GlaDOS has so far been shown to have control over all the systems in the entire facility, she notes that her morality core, which you destroyed, "must have had some ancillary responsibilities" and thus she is unable to deactivate the turret.
 * Portal 2:
 * It initially averts this; GLaDOS has learned from the last time and presents you instead with what would be a completely lethal trap, if you and Wheatley hadn't.
 * Likewise, although claims to have studied footage of GLaDOS' defeat and doesn't make the same mistakes, he makes entirely different mistakes instead, building his "lair" near convenient gel tubes and hurling bombs at you instead of waiting for the neurotoxin to do its work. Mostly justified though, as  He also tries turning the bombs off after you hit him the first time, but he's apparently too damaged to do so, like GLaDOS above.
 * The room you fight in has no viable portal surfaces (your only method of attack) before Conversion Gel tubes start bursting, so his plan was almost airtight. Unfortunately, somebody was stupid enough to try throwing bombs at someone standing behind a Conversion Gel tube, causing it to spray everywhere. After the sprinkler system activates and wash away the gel he even comments on how he should have triggered it himself if only he had known it would work (or been able to turn them on, given his state at the time).
 * Many Legacy of Kain bosses fill this trope perfectly. In Soul Reaver, Rahab's chamber consists of windows you have to break to shine sunlight on him, while Melchiah's chamber has retractible portcullises you have to lure him through to have them fall and hit his back. In Blood Omen 2, Faustus stands atop furnaces in a room full of mist, which you can use to become invisible and sneak up close enough to turn the furnaces on and burn him. In Defiance, Turel's chamber has four gongs that ring loudly and stun him when rung. The third boss of Blood Omen 2, Sebastian, isn't so much Boss Arena Idiocy as it is he's plain stupid -- he crawls along the walls and leaps at you, and there's a laser in the center of the room. If you stand on the other side of the beam, Sebastian will leap into it to try and hit you, and hurt himself in the process.
 * Darksiders is full of this.
 * The first boss, Tiamat, would be unbeatable if her arena wasn't surrounded with torches and bomb flowers. The second boss, the Griever, is defeated with a freight rail carrier that War can punch into her gut. Straga's own weapon and the floor of his own arena are both used to kill him.
 * In the Griever's case, it's not technically her fault -- she has no idea you can move something that big. Tiamat can allegedly be defeated using only your Crossblade without the bombs.
 * World of Warcraft has several:
 * It would be nearly impossible to defeat Anub'arak in the Crusader's Coliseum save for the conveniently placed frost orbs floating around his lair which, when knocked down, form icy patches on the floor that prevent his minions from burrowing and stun him when he runs into them.
 * Karsh Steelbender in Blackrock Caverns is almost invulnerable to player damage unless he's lured into the molten metal conveniently pouring down out of his forge. Of course, doing this also causes him to inflict massive fire damage to the entire party.
 * In Naxxramas Instructor Razuvious hits hard enough to make him nigh-untankable. However, his nearby students can be mind-controlled by priests and sent to soak up his hits. It's even worse in the 10-man version, where for no particular reason (save for the fact that a 10-man raid may not have people who can mind control) there are mind-control orbs sitting right there that anyone can use. That's just asking for trouble.
 * Professor Putricide in Icecrown Citadel would kill the entire party with pools of ever-growing slime if he did not conveniently have a bottle on his desk that transforms the person who drinks it into a mutant monster that eats this slime.
 * The Ulduar Flame Leviathan and indeed the entire section leading up to it would be pretty much impossible if a bunch of siege engines hadn't been left right by the entrance. The Flame Leviathan would also be much harder if there weren't barrels of pyrite floating all over that can be shot down and it tricked into running over or shot at it by the vehicles.
 * Brann and the other allies who show up built the siege engines from salvaged Titan technology.
 * The blind dragon Atramedes of Blackwing Descent makes the mistake of fighting your group in a room where the walls are lined with shields that can be smacked like gongs to deafen and disorient him. It goes without saying that this is the only way to beat him.
 * Also from Blackwing Descent, Chimaeron is a boss that deals massive amounts of damage for his level -Massive enough that the fight would be impossible if not for the Bile-O-Tron, a device that prevents Chimaeron's attacks from killing anyone who has more than 10,000 health. This case is partially justified in that the Bile-O-Tron was built by a gnome Nefarian was keeping prisoner and was not supposed to be there, but then, one has to wonder how Finkle managed to build it while caged in the first place (or sneak it in when he was captured, if he'd done so already).
 * Magtheridon has five cubes that must be used to banish him when he uses Blast Nova. Justified in that Illidan's forces were keeping him prisoner there.
 * Razorgore the Untamed has a mind control device in his room, which you need to use to make him destroy the eggs before you can defeat him.
 * Bloodlord Mandokir is able to instantly kill any player with almost all of his attacks. Good thing he chooses to fight you in an arena surrounded by benevolent spirits who can resurrect you and make you stronger.
 * Morchok from Dragon Soul is another example. He summons huge earthen spikes right before casting Black Blood of the Earth. The spikes themselves don't serve any purpose except for the players to hide behind to completely avoid damage from Black Blood of the Earth, which, if stood in, will kill you after a fairly short amount of time. Basically, he'd easily wipe the group if he didn't also summon those spikes for no apparent reason. In a similar vein, the final boss of Sethekk Halls charges up a massive Arcane Explosion that does fatal damage, but is easily blocked by hiding behind one of the several pillars he has in his room.
 * The Spine of Deathwing fight takes place with the entire raid riding on Deathwing's back. At various points in the fight, he will attempt to shake the players off by rolling. This is potentially a One-Hit Kill on the entire raid, but it can be avoided by using the numerous tentacles sprouting from Deathwing to secure yourself to his back. Though Deathwing didn't put the tentacles there intentionally (the sheer amount of power he's absorbed is causing his body to mutate and collapse) one has to wonder why he does not simply slam his back into the ocean he's flying over and crush/drown the players.
 * In Ratchet and Clank, the Snagglebeast has a shield which can deflect any type of projectile. The only thing that can hurt it while the shield is up is falling into lava. Not only is the arena full of lava, the boss is too heavy to cross the bridges over it.
 * Transformers: War for Cybertron has this twice: Omega Supreme fights you near energon tanks you can taint with dark energon to make him vulnerable. Trypticon fights you near energon tank conveyor belts, which can be made to detonate and are the sole things capable of damaging his shoulder cannons.
 * In Silent Hill 4, Walter and the "god" he summons are completely invincible... except for the spears that spawn in the very place where you fight him.
 * Chrono Trigger:
 * A recurring invincible boss named Ozzie is beaten twice. Both times involve attacking other objects to cause him to fall through a trap door.
 * Is this even possible in an RPG? He found a way.
 * Lyran, a Lich in Baldur's Gate: Dark Alliance 2, chases you throughout his castle before locking you in the Ossuary in order to do battle with you properly. Before you enter the Ossuary he's completely invincible; once inside you can find his mortal remains and destroy them in order to damage him.
 * Baron K. Roolenstein in Donkey Kong Country 3. If he hadn't installed levers in the ceiling that drop barrels, the kongs would have no way to hurt him.
 * The bosses in Donkey Kong Country Returns were generally good about choosing locations that weren't potentially lethal towards them if utilized properly by Donkey and Diddy. The one glaringly obvious exception was Mangoruby, whose boss chamber contained three wheels with switches on them that, when pounded, would de-electrify Mangoruby's body and allow Donkey to Goomba Stomp her.
 * Gol and Maia in Jak and Daxter The Precursor Legacy. If they just removed the Blue Eco Launcher, their bombs would kill Jak in 20 seconds flat.
 * Mortal Kombat Deception features Onaga, who is stunned when you destroy (touch) one of six objects called kamidogu, which are the source of his power. Naturally, he places them along the fringes of the arena, spaced 60 degrees from each other.
 * From Medi Evil 2:
 * The Last Elephant-bot enemy fought in the Freakshow can't be damaged by Dan's normal weapons, but the cranes can be used to crush it by dropping spare parts on it.
 * The Count suffers from both this trope and Tactical Suicide Boss; the first stage of the fight requires you to use mirrors to reflect his spells back at him, and the second has you aligning them so that they reflect sunlight onto him, causing him to burn.
 * Okami has several bosses like this. The Spider Queen is completely immune to your attacks, her only weakness being her eyes inside her abdomen. But, oh, look! All around the arena are conveniently placed flowers that are here for no reason at all and that you can use to grab her hooks and open the Queen's abdomen, exposing her weak point! Kyuubi, Lechku & Nechku and Yami's Boss Rooms are also full of lava, water and thunder without which you wouldn't be able to do a thing to them.
 * Dagoth Ur of Morrowind fights you (after a short introduction where he grants you the first blow) in a room that also houses the source of his power, the destruction of which would make him mortal. Granted, he wouldn't have reason to expect you to be willing (or even know how) to destroy that source, and he has to hang around the place anyhow to keep the Tribunal from sneaking in and renewing their power...
 * Spiral Knights: The Snarbolax is invincible unless the Beast Bell in his boss room is rung when he's close enough for it to stun him. The Roarmulus Twins are immune to Knights' weapons, but not their own missiles; the Twins are placed directly across from each other with switchable walls between them.
 * Angry Birds generally has no bosses, however, in its Crossover with Rio, we are treated to two bosses from that movie. These bosses are surrounded by explosives and rocks that allow the player to inflict even more damage than the birds ever could.
 * A non-video game example is in the American Dad episode "Dungeons And Wagons". While playing an MMO, Jeff and Haley are trying to get an amulet that can resurrect Steve's character, and must contend with a massive monster that is almost invulnerable. Jeff notes that "They always put in a way to win," and spots... a scuba tank on a ledge in the room. They throw the tank into the monster's mouth, and Haley shoots it with an arrow, causing it to explode. There was really no conceivable reason for the scuba tank to be on a ledge in a mountain temple in a fantasy game, so this one must be chalked up to Rule of Funny.
 * The Dragon God in Demon's Souls would be unbeatable...if it weren't seated right between two huge ballistas pointed at its shoulders.
 * The boss of the theater level in Psychonauts is slightly smarter than most in that he destroys the spotlights once you've used them to stun him. He's still not smart enough for basic patern recognition, and ignores the other identical spotlights who are all within spitting distance of each other. Even after you succesfully used the first two on him, he doesn't think to destroy the third.
 * In Beyond Good and Evil there are some Alpha Section guards who, unlike the rest, don't have an air tank (thus, they are immune to the usual tactic for disabling them). Whenever you face them, they either can be sneaked past, or they are standing next to a moving platform that can be activated to send them to their doom. The Alpha bases also contain military robots that cannot be destroyed using conventional attacks; however, they can always be pushed into an electric barrier conveniently placed nearby, destroying both the robot and the barrier.
 * Aaron from Clive Barker's Undying wields a chain that he uses as a whip against you. The only way to defeat him is to position yourself in front of one of the rings on the wall and dodge his attack. His chain will get trapped in the ring, and you can attack him while he's busy trying to get the chain out.