History ThatOneBoss / RPG

* In [[VideoGame/EvolutionWorlds Evolution: The World of Sacred Device]], the final encounter with Eugene Leopold. The first fight with just him is somewhat of a pushover, but then cue him showing up in a HumongousMecha. What mainly makes him so dangerous is a machine gun attack he loves to use that hits the entire party TWICE, and can poison them with a high chance. And even then he takes a ton of punishment and will sometimes heal himself for 3000 HP. On top of this, he's ALWAYS be at or above the level of the main character, AND since you're forced to always use your WhiteMage up until this point, [[FakeDifficulty you'll now be forced to have other means to heal and buff]] [[DistressedDamsel since she's been kidnapped.]] The main character can get some, but only if you've actually been exploring the ruins and not just rushing to the end of each one. And if you start the sequence to get up to the boss, [[PointOfNoReturn you aren't going back to town until you've beaten the game.]]

*** During the raid on [[StoneWall Kwanda Rosman's]] fortress, you have to fight TheDragon [[JustForPun which is actually a real dragon]] and have to deal with a fixed team, and also the fact that the dragon has incredibly high health and evasion which will make most of your physical attacks completely useless which will make things a lot tougher considering you don't have access to really powerful magic at that point in the game.

* ''VideoGame/AgarestSenki2'' may not be crossing the NintendoHard line, but that doesn't mean that this game doesn't have the resident ThatOneBoss. Pain, thy name is [[spoiler: Sophia, one of your party members. She herself]] as a boss really isn't that hard. What makes [[spoiler: her]] hard is if you did not have any back up party members due to the fact that at this point, you lose ''four'' of your party members due to a series of [[PlayerPunch PlayerPunches]]. Oh, and this is also a case of BossRush due to the fact that before you even fight [[spoiler: her]], you are fighting off against two bosses who aren't hard themselves. However, whatever HP you have left at your last fight, it still carries over to this fight. And woe befall to you if you didn't equip your reserves with any equipment due to the fact that the game will not allow you to change equipment while in this section. [[spoiler:Her "Eternal Gleam" [[LimitBreak Original Skill]] should '''not''' be taken lightly however, as it's '''more than capable''' of OHKOing your '''[[TotalPartyKill entire party]]''' should your party members not be spread out enough so that at least one or two party members survive.]]

* ''VideoGame/AgarestSenki2'' may not be crossing the NintendoHard line, but that doesn't mean that this game doesn't have the resident ThatOneBoss. Pain, thy name is [[spoiler: Sophia, one of your party members. She herself]] as a boss really isn't that hard. What makes [[spoiler: her]] hard is if you did not have any back up party members due to the fact that at this point, you lose ''four'' of your party members due to a series of [[PlayerPunch PlayerPunches]]. Oh, and this is also a case of BossRush due to the fact that before you even fight [[spoiler: her]], you are fighting off against two bosses who aren't hard themselves. However, whatever HP you have left at your last fight, it still carries over to this fight. And woe befall to you if you didn't equip your reserves with any equipment due to the fact that the game will not allow you to change equipment while in this section. [[spoiler:Her "Eternal Gleam" Original Skill should '''not''' be taken lightly however, as it's '''more than capable''' of OHKOing your '''[[TotalPartyKill entire party]]''' should your party members not be spread out enough so that at least one or two party members survive.]]

* ''VideoGame/AgarestSenki2'' may not be crossing the NintendoHard line, but that doesn't mean that this game doesn't have the resident ThatOneBoss. Pain, thy name is [[spoiler: Sophia, one of your party members. She herself]] as a boss really isn't hard at all. What makes [[spoiler: her]] hard is if you did not have any back up party members due to the fact that at this point, you lose ''four'' of your party members due to a series of [[PlayerPunch PlayerPunches]]. Oh, and this is also a case of BossRush due to the fact that before you even fight [[spoiler: her]], you are fighting off against two bosses who aren't hard themselves. However, whatever HP you have left at your last fight, it still carries over to this fight. And woe befall to you if you didn't equip your reserves with any equipment due to the fact that the game will not allow you to change equipment while in this section.

** The Golem Twins you meet in the Ocean Palace. Earlier, you fought one in a semi-HopelessBossFight (it's winnable but not necessary), but this time you have to win, and the twins will not make it easy on you. Aside from powerful normal attacks, which they switch up depending on the skills you use on them, they also possess the nasty PercentDamageAttack Iron Orb, which will instantly cut your HP in half, no ifs, ands, or buts (which is their response to physical attacks, meaning at least some of the pain will be mitigated if you go all-magic, but if you brought [[BareFistedMonk Ayla]], she won't be much help). It gets much easier if you can take out one of the golems, but that's a feat in itself.

* The fight against the [[EvilKnockoff copies of the Crystal Gems]] in ''VideoGame/UnleashTheLight''. Like in the original game, boss can heal, has {{Status Infliction Attack}}s, and the copy of Amethyst being able to hit your entire party, though they don't start off especially strong. That is because [[KillOneOthersGetStronger every time you kill one of the copies, the rest get healed along with getting a buff to their stats]]. Killing just one of them causes a big spike in difficulty, the stat buffs mean the copies of Pearl and Garnet can inflict massive amounts of damage, the latter being able to potentially KO characters who launch close range moves via her counterattacks, and the copy of Amethyst inflicting heavy damage to your entire party. When the Amethyst copy gets the Flaming Gauntlet buff, she can [[DamageOverTime burn]] ''your entire team'' as well, and it ''stacks''.

* ''VideoGame/{{Undertale}}'': [[MonsterKnight Undyne]], the boss of Waterfall. No matter which route you take, she is likely to give you hell. ([[GoldenEnding True]]) PacifistRun? You fight her [[LowLevelRun with your starting HP]] and can't attack her while she showers you with barrages of magical spears that you can't dodge and instead have to [[UnexpectedGameplayChange block with a magical shield.]] The only way to defeat her without killing her is to [[spoiler:run away from the fight, then run until she inevitably catches up, and then repeat until she collapses from exhaustion, which is only hinted to even be possible, let alone required, by a single line of dialogue just before the fight -- and even then it can be only done when she changes her attack pattern for a few turns]]. She gets a bit easier on a Neutral Run, where you don't have to bother with the [[ThouShaltNotKill no killing rule]] before or during the fight, [[TheDeterminator but even after having 0 HP, she still fights on for a few rounds]] -- but then comes the Genocide Run, where she seemingly turns into a {{Zero Effort|Boss}} CutsceneBoss... and then she becomes [[OneWingedAngel Undyne the Undying]], beating the crap out of the player with new, much faster, stronger and more random versions of her two regular attack patterns, with several new attacks thrown in. One way or another, defeating Undyne will take you a while.

* ''VideoGame/{{Undertale}}'':
** [[MonsterKnight Undyne]], the FinalBoss of Waterfall. No matter which route you take, she is likely to give you hell. ([[GoldenEnding True]]) PacifistRun? You fight her [[LowLevelRun with your starting HP]] and can't attack her while she showers you with barrages of magical spears that you can't dodge and instead have to [[UnexpectedGameplayChange block with a magical shield.]] The only way to defeat her without killing her is to [[spoiler:run away from the fight, then run until she inevitably catches up, and then repeat until she collapses from exhaustion, which is only hinted to even be possible, let alone required, by a single line of dialogue just before the fight -- and even then it can be only done when she changes her attack pattern for a few turns]]. She gets a bit easier on a Neutral Run, where you don't have to bother with the [[ThouShaltNotKill no killing rule]] before or during the fight, [[TheDeterminator but even after having 0 HP, she still fights on for a few rounds]] -- but then comes the Genocide Run, where she seemingly turns into a {{Zero Effort|Boss}} CutsceneBoss... and then she becomes [[OneWingedAngel Undyne the Undying]], beating the crap out of the player with new, much faster, stronger and more random versions of her two regular attack patterns, with several new attacks thrown in. One way or another, defeating Undyne will take you a while.
** Asgore Dreemurr, the King of Monsters, on a Neutral-Pacifist run[[note]]Since you can't get the [[GoldenEnding True Pacifist]] ending on your first playthrough, this type of run is the best you can do at first, although it cuts a lot of work out of getting the GoldenEnding[[/note]]. Since he ''[[InterfaceScrew destroys the Mercy button]]'' before the fight begins, ''[[ButThouMust forcing]]'' you to fight him, and has lots of health and very damaging attacks [[LowLevelRun compared to your own low stats]], it'll take a long time before he goes down, especially if you're unused to using the FIGHT command (which you won't have used much, if at all, during a Neutral-Pacifist run), and his attacks are hard to dodge.
** The FinalBoss of the Genocide Route, [[spoiler:[[CrouchingMoronHiddenBadass Sans the Skeleton]]]], who decided to [[LetsGetDangerous take matters into his own hands]]. His attacks can only deal ScratchDamage and he himself is a OneHitPointWonder... thing is, said attacks ignore MercyInvincibility, making you recieve ''[[DeathOfAThousandCuts one hit point of damage per frame]]'', and each frame applies a stacking DamageOverTime effect as well. As for killing him in one hit -- it won't happen since he ''dodges your attacks.'' On top of this, his own attack patterns are ''gruelling''; he opens [[CombatPragmatist using one of his most powerful attacks before your first turn]] (meaning you can die before you even see the battle menu) and then starts throwing barrages of fast, hard-to-dodge attack patterns at you... and ''then'' he reveals he was ''holding back'' and starts [[ConfusionFu switching patterns mid-attack]], [[WeaponizedTeleportation teleporting the player into the way of his bullets]], and [[InterfaceScrew attacking the player during their own turn.]] The interesting thing about this boss is that everything about him is [[InvokedTrope purposefully designed]] to be as rage-inducing as possible. He ''knows'' about your ability to SAVE and LOAD and, by extension, that he can't actually beat you in a fair fight, as you'll just keep reloading until you finally get the upper hand. So instead he purposefully taunts you, breaks the rules, and generally tries to be as big of a pain in the ass as possible, all in the hopes of making you RageQuit.
*** Hell, he's this ''in-universe''. [[spoiler:Flowey the Flower]], who had the power to SAVE and LOAD before you, says that this guy was a pain in the ass to beat, and was entirely unable to whenever he showed up to put a stop to things.

* The fight with the Solidum Telethia ranks as (one of) the hardest in ''VideoGame/XenobladeChronicles1'' for many players. It's not really the Boss himself that's the problem: it's Tyrea who fights alongside him. The Telethia will evade any and all attacks unless you use Purge on it. easy enough. But you've only got so much time before the effects of Purge wear off and it begins attacking again. This is annoying but not impossible. Tyrea makes it worse because not only is she capable of attacking any of your characters, she's also capable of casting a Shield on the Telethia, making damaging him very difficult indeed. Now you may think it's easy to get around this, just take Tyrea out first right? WRONG! The Telethia likes to use a move that's kinda like Pokemon's Follow Me, as it forces you to attack the Telethia himself. Oh, and if you're using [[TheHero Shulk]], which you probably are since only him can silence the Telethia, all his attacks will do ScratchDamage to Tyrea. Fun times. (Though at least if you die to this boss, you will respawn outside the room with Melia back in your party and you can now teleport to landmarks and level up if need be, where you previously couldn't in the High Entia tomb)

** And the mother of all of them, Disciple [[spoiler:Lorithia]]. Flunkies with sizable health bars that you need to take down or your physical damage to the boss will be nerfed to hell (until [[OhCrap they're brought back]]), attacks that cause StatusEffects (The really bad ones, too), high HP, and worst of all, the area is surrounded by acid pools that cause your HP to start going down fast. Your computer-controlled allies [[ArtificialStupidity are too dumb to run out of the pools]] and she is so large she will often push your party into them. And to top it all off…[[BrokenRecord "You'll pay for your insolence! You'll pay for your insolence! You'll pay for your insolence!"]]

** Notably from Orzammar is a fight against several Yellow/orange enemies, including a Templar (who is basically a toned down Revenant with higher health/damage), a Blood Mage (who is broken by sheer merit of being a blood mage), and dangerous mooks.
** The more notable boss of the Dwarfs recruitment mission is the Darkspawn Broodmother. As if her grotesque appearance and horrific origin story aren't bad enough, there's the boss fight. The Broodmother has high levels of health, summons many tentacle ads that can stun the player along with Darkspawn ads. Players attacking her in combat can be grabbed and subjected to a one hit kill or an [=AoE=], that both involve vomit (literal NauseaFuel).
** At the end of the quest to rescue Queen Anora, the player is confronted by one of Loghain's CoDragons Ser Cauthrien. In addition to being Level 19 and having almost as much health as a ''High Dragon'', she's also backed by [[HopelessBossFight ten archers, two swordsmen, and a mage.]] The player is given the option to surrender, and if they do so or lose the fight [[PrisonEpisode they and possibly Alistair are taken prisoner]]. Unless the player knows about the fight in advance and completely prepares for it, this is guaranteed to be a CurbStompBattle. It's not uncommon for players to need about 50 health potions during the fight, and it's extremely difficult to avoid being stunned from ten directions at once before taking hundreds of points of damage from Cauthrien and her swordsmen.

** Then there's Jarvia. Ever wondered what it would feel like to take on a dozen rogues at once, including ones who are higher-level than yours? Wonder no more! Jarvia will thoughtfully bring along as many thugs and assassins as you could hope for, while using hit-and-run tactics where she repeatedly drops into stealth, runs back behind a fireball trap, and then comes out again once you're well and truly pummelled. Attacking ''anything'' leaves you open to attacks from everyone else, and most of them have stun, backstab, and/or stealth abilities that they use to persistently dish out massive damage. The net result typically involves reloading from the autosave many, many times.

* ''VideoGame/BravelyDefaultII'': Glenn, the holder of the Salve-Maker asterisk. He only has a few moves he'll use, but all of them are painful. He can mix up a Gigapotion to heal himself for 5,000 health out of his 35,000 total (and you can find him when your level is in the low thirties, so your characters can only break 4,000 in specific equipment and job setups), he can mix up a nasty attack that deals 1,500 damage to each character and inflicts Contagion, and he can use Philtre to charm one character. The latter two of those are two of his three counter-attack moves, with Philtre coming off of physical damage and the 1,500-to-all as "Counter Any Damage". You want magical damage? He'll counter that with [=BP=] Tonic. Other turns, he'll Default often to build up for a two-Attack, 1,500-to-all, Philtre medley of pain. Run him out of magic points? You're cute, that only stops his Philtre. Poison him? Gigapotion can't be stopped. The one mercy is that he is not a mandatory story boss, but should you desire his Asterisk...

** Ophilia, Chapter 2: [[spoiler:Hróðvitnir, a monstrous wolf]]. This boss is going to make sure that the Kindling will not be a fun journey, let alone an easy one. The instant the fight starts, it gives itself a buff that lets it act twice per round, and it makes full use of attack buffs, attack and defense debuffs, and party attacks to maximize its durability and endurance. Ophilia is required for this fight, and while her healing spells will serve you well, she has Physical Defense equivalent to soggy toilet paper at best[[note]]She has great Elemental Defense, so naturally [[spoiler:Hróðvitnir]] is a physical attacker to render this upside pretty much null and void during this fight[[/note]], meaning she stands to die pretty often, along with some of your other squishies. [[spoiler:As the fight wears on, things go FromBadToWorse as it introduces, in order, the ability to increase its maximum guard points (acting twice per turn means it doesn't have to sacrifice an attack to do this), a party-wide debuff to disable your boosting, and the ability to act '''thrice''' per round]]. Have fun with that!
** Cyrus, Chapter 2: [[spoiler:Gideon, the MadScientist of dark magic]]. His weaknesses are covered as long as his undead minions are alive. Said minions hit hard, as does the boss himself, with Executioner being an almost guaranteed OneHitKill move. He's also fond of using debuffs and Terror on your party to make life difficult for you.

** The Balor in the Underdark, which must be killed if you play a good character, is the first high-level demon you'll meet in the game (outside SequenceBreaking or BonusBoss-esque shenanigans). It is immune to weapons of +2 quality or less (which will be the majority of your weapons at that point), and opens the battle with a party-hitting paralysing effect followed by spamming Vampiric Touch and a fire-damaging gaze. It can quickly wipe an unprepared party and unless you know the setting lore well enough to identify it by name, can quickly catch you unprepared.

** Another obnoxious opponent is Chilldream, who stands out as the only opponent in the game who isn't a BonusBoss but can do something [[TheComputerIsACheatingBastard your character can never do]] -- shooting 20 high attack bolts at once (your max is 15). Since Chilldream has maxed out attack power, that means 50 unblockable damage per round unless you got the High Defend Bonus skill (which is mutually exclusive with Low Attack Bonus, the latter of which is much more useful in literally every battle except this one). This assumes he doesn't simply cast Freeze Defend, which deals 100 unblockable damage. This, in a game where you might have 400 HP in time for the ''final boss'', and are likely to have under 200 around the time you can first face Chilldream. The saving grace is that it's possible to avoid facing him with clever use of the game's Relationship system, though doing this causes you to gain Reputation points (when on the Black path you want as few of these as possible, and Black players are the only ones who have to face Chilldream in the first place.)

** Polis Police, the second boss you fight on Disc 2. If you didn't defeated the BonusBoss and got the rewards from it before coming here, '''you're already screwed as hell.''' Polis Police has not one, but ''two'' attacks that instantkill anyone thanks to it's huge damage. Not even Serge is safe from this guy. ''And it's not even 10 minutes since you switched the CD.''

*** The FinalBoss: [[spoiler:Lady/Grace Garland and Malice Umbral]] is ''harder than most of [[BonusBoss Bonus Bosses]]''. First, they are two, so they can ''and will'' abuse the (Double) Combo mechanic against you. Note that their attacks hit already hard even when not comboed, and most of their attacks inflict Chain status so that next attack hurts even more. They are also fond of status attacks to cripple you or your Judgment Ring. The worst is however that [[spoiler:Lady]] will use a move Lost Progress, which dispels all your buffs, after you use any buff. To really punish you for trying however, she will ''skip her turn'' to dispel you immediately after you applied the buff (so no Entrance or the similar one-time buffs) and ''then she will get an extra turn'', meaning you must basically do entire battle without buffs.

** And if you thought Leo Cantus was fun now, wait until you see [[VideoGame/NEOTheWorldEndsWithYou Leo Cantus Armo]]. While there are no stylus motions, anyone who thinks they can just use one psych at a time against him is zetta slow in the head, as he will dodge that psych unless he's armored... and when he is armored, you have to chip at it before he starts taking regular damage. Add in that he's fast and strong with wide-reaching attacks, and you've got quite the fight ahead of you. It's important to note that you only have five psychs available to you by this point, and you don't get your sixth until after this showdown. There's also [[BonusBoss Felidae Cantus]] if you're feeling masochistic.

* Gynophobia, the second-to-last boss of [[spoiler:Oersted]]'s chapter in ''VideoGame/LiveALive'', makes the final boss of the chapter feel like a mook. She comes with two attacks: Sweet Whisper and Enchantment. Sweet Whisper puts you to sleep and inflicts Drunk, which shuts off all but one of your attacks, while Enchantment does massive amounts of damage and heals her for the damage done. Enchantment only hits at close range, but Sweet Whisper covers much of the arena -- and your character's range is minimal in comparison, forcing you to fight within its hit radius. What's more, if you failed to find [[spoiler:the hidden field of healing grass]] earlier in the chapter, you may well end up fighting Gynophobia without ''any means of healing yourself''.

** And the mother of all of them, Disciple [[spoiler:Lorithia]]. Flunkies with sizable health bars that you need to take down or your physical damage to the boss will be nerfed to hell (until [[OhCrap they're brought back]]), attacks that cause StatusEffects (The really bad ones, too), high HP, and worst of all, the area is surrounded by acid pools that cause your HP to start going down fast. Your computer-controlled allies [[ArtificialStupidity are too dumb to run out of the pools]] and she is so large she will often push your party into them. And to top it all off…"You'll pay for your insolence! You'll pay for your insolence! You'll pay for your insolence!"

** Barubary. He's statistically the strongest enemy in the game (this includes the final boss, by the way, never mind that said final boss is freaking '''[[spoiler:[[DidYouJustPunchOutCthulhu G]][[GodIsEvil O]][[UltimateEvil D]]''']]). And to get a clue about the [[InfinityPlusOneSword Infinity Plus One Accessory]] location, you have to face him ''alone''. With no reduction in his stats. You do get free healing before the fight though if you do so.

** Machine Tyrant as well has attacks that track players and do a lot of damage if they hit, combined with a powerful AoE attack that sometimes hits at the same time, and can be a challenge to unexperienced players when first encountered, due to the amount of attacks players need to keep track of.
* "Mining Helgak" from ''VideoGame/SepterraCore''. You meet it halfway through the game, before you get to do much LevelGrinding and he is one of the strongest bosses, at least in HP. Somewhat understandable, since the game is greatly influenced by (to avoid the phrase "rips off") ''VideoGame/ChronoTrigger'', and the minig helgak is modelled after Lavos, most likely from HopelessBossFight in Ocean Palace.

** The FinalBoss of the [[KillEmAll Genocide Route]], [[spoiler:[[CrouchingMoronHiddenBadass Sans the Skeleton]]]], who decided to [[LetsGetDangerous take matters into his own hands]]. His attacks can only deal ScratchDamage and he himself is a OneHitPointWonder... thing is, said attacks ignore MercyInvincibility, making you recieve ''[[DeathOfAThousandCuts one hit point of damage per frame]]'', and each frame applies a stacking DamageOverTime effect as well. As for killing him in one hit -- it won't happen since he ''dodges your attacks.'' On top of this, his own attack patterns are ''gruelling''; he opens [[CombatPragmatist using one of his most powerful attacks before your first turn]] (meaning you can die before you even see the battle menu) and then starts throwing barrages of fast, hard-to-dodge attack patterns at you... and ''then'' he reveals he was ''holding back'' and starts [[ConfusionFu switching patterns mid-attack]], [[WeaponizedTeleportation teleporting the player into the way of his bullets]], and [[InterfaceScrew attacking the player during their own turn.]] The interesting thing about this boss is that everything about him is [[InvokedTrope purposefully designed]] to be as rage-inducing as possible. He ''knows'' about your ability to SAVE and LOAD and, by extension, that he can't actually beat you in a fair fight, as you'll just keep reloading until you finally get the upper hand. So instead he purposefully taunts you, breaks the rules, and generally tries to be as big of a pain in the ass as possible, all in the hopes of making you RageQuit.

*** The Carn Dun Captain is Wulfrun cranked UpToEleven. He constantly teleports, bombards you with fire and summons hordes of tough enemies that will kill you in seconds if you get surrounded. The only way to safely take him down is to shoot him with ranged weapons which takes forever if you don't have the right upgrades.

** Haniel and Michael (Vesper and Decus). First, they're the first boss fight that the bosses have voices in, and they ''taunt'' you to start: "You insignificant ''bugs!''" and "I WILL BURN YOU TO THE BONE!" They then proceed to do [[ExactlyWhatItSaysOnTheTin just that]], with Decus throwing out a fire-based physical attack that is easily capable of one-shotting the whole party and Vesper backing him up with a beam move which hits multiple times and causes status ailments. Add to this the fact that LevelGrinding takes forever in the area since the random fights don't give a whole lot of experience, and you've got a recipe for good old fashioned controller throwing.
** There's also the Bark which has high health, defense, and only one attack called "Lost Patience" (how appropriate) [[ThisIsGonnaSuck which hits the entire screen and the team for an incredible amount of damage.]] [[spoiler: Later you can go to The Cave Of Trials, and find out it has an evolved form which is a boss of one the floors, and then becomes a regular enemy on later floors which takes this fight UpToEleven.]]

** The Grigori bosses are usually be tons more difficult than anything else you've faced in the area they appear and they have certain points on their bodies which must be hit if you are to do anything resembling decent damage. It doesn't help with the fact that said weak spots are pretty much stupidly difficult to unveil, let alone hit.

** Commander Cherenkov's Gnosis form in Episode I qualifies, also. Not only is it him (in a surprise battle, nonetheless), he also gets two pain-in-the-rear minions with an area-of-effect attack and that's not all: if one of the minions is killed, he gets a stat boost, if he is hurt while the minions are alive, there is a high chance that they will heal him double the HP an average leveled party can take out of him in one turn; if both minions are killed, Cherenkov's stats triple, meaning he can kill any party member (except [[MightyGlacier Ziggy]]) in two hits, and there is a substantial chance he will get two turns in a row. [[UpToEleven Worth mentioning]], he's the [[WakeUpCallBoss first enemy]] the player encounters who can and gladly will [[OhCrap seal the ether abilities of party members, rendering healing if not impossible much, much less effective.]]

** Stone Coatl is the definition of ThatOneBoss. He takes all the annoying bits of these previous fights and [[UpToEleven turns them up to eleven.]] The fight starts with [[GoddamnedBats Tiny Terrors and Witch Doctors]], the second of which can heal their allies and slow you down considerably. After each wave of Animated, you fight a Mask of Death and Rebirth, which could [[BossInMookClothing qualify for this trope in their own right, despite being "mooks"]]. And the last wave of monsters before you even fight the boss ''itself'' are Bladed Vases which have a ridiculous area of effect attack that deals heavy damage in a circle to anyone even kind of sort of near it. Oh and if you don't work fast, the vases can easily wipe out a party because they keep spawning until a certain number is reached. Finally, when you reach Stone Coatl, he has the most HP out of any boss you've fought, has several different attacks, one of which ''knocks you back across the entire screen'' when you've been to close to him during the fight, and he spawns an infinite number of Animated which can be any or all of the types previously mentioned. Stone Coatl is easily harder than the final boss.

* ''VideoGame/MassEffect1'':
** The... ''beloved'' krogan battlemaster at the end of Therum. While not too hard by himself, having fairly reasonable health and dealing moderate damage by endgame standards, most players go there fairly early on to get Liara. Most players have, up to this point, had a relatively easy time of it. And thus most players will die immediately. What makes it even more frustrating is that the game will not autosave immediately before the fight, so you'll end up getting reeeeal familiar with the dialogue immediately before.
** Matriarch Benezia uses her biotics to move your cover or cripple you, and to make matters worse, you have to deal with Asari Commandos and Geth Snipers (which can kill you in one hit, by the way) in three separate waves. The level seems designed to make the battle as hard for you as possible, with virtually no solid/stationary cover, plenty of ways for enemies to flank you, and narrow walkways that [[CameraScrew drive your camera positioning insane]] whenever you're flung into their walls by Throw or Neural Shock. Worst of all, the battle is glitchy as hell; if you don't constantly shut down enemy biotics with Damping or your own biotics, be prepared to be flung into a stair or handrail and get stuck until you die, restart, or ragequit.
* ''VideoGame/MassEffect2'':
** Praetorian is a good contender for the hardest fight in the game. First, it's a flying tank that can fire a powerful laser beam at you, [[GangUpOnTheHuman and often only you]], with perfect accuracy. It has a barrier that is difficult to bring down before you can even begin to deal damage to it. Once you take that barrier down, it will wait a few seconds and then slam itself into the ground, setting off a shockwave that stuns anyone nearby. Once the stun wears off, you have only a second to get away before the boss sets off an energy pulse that is almost always a one-hit-kill to anyone within a few yards. Then it will rise back into the air with its barrier fully recharged. The final kicker? It will always slowly float towards you, so while you're hiding under cover to keep away from its laser beam, it's getting closer and closer to getting you with the insta-kill energy pulse. For a game that is mostly tough but fair, such that if you die you'll know what you did wrong and how to do better next time, Praetorian suddenly crosses the line between challenging and NintendoHard. There are only two in the game (which are both ThatOneLevel to boot) and they're more than enough.
** The thresher maw. This is a giant [[SandWorm worm thing]] with massive armor that shoots poison that can kill you in two hits and can only be hit at range. Fortunately you don't ''have'' to kill it, and can simply hide while the timer counts down, but it's a deceptively long time.
** The Geth Colossus. Not so bad in the first game when you could drive circles around it while whittling its shields down with your vehicle-mounted cannon. Here, you're fighting it on foot with small arms, and it has cover and infantry support. And it can ''heal itself''. On Hardcore or Insanity (which you have to do in order to get the Bonus Weapon) the thing fires its pulses really fast to keep you in cover while its buddies run around and kill you.
** Tela Vasir in the ''Lair of the Shadow Broker'' DLC is easily one of the toughest bosses in the series. She has '''extremely''' high barrier and armor defenses. She's ridiculously accurate with her battle rifle, uses a [[GetBackHereBoss biotic charge]] (something that only Vanguard Shepard was capable of before), shockwave, and tech armor.
** Kasumi's Stolen Memory DLC has Donovan Hock at the end of her loyalty mission. At first it seems like a standard gunship battle, of which there are two in the main game. This one is different however, in that squadrons of Eclipse mercenaries and LOKI mechs will continually spawn that you have to take care of while Hock pelts you with fire from his gunship. When you deplete the ship's shields, they simply '''regenerate to full'''. The way the cover on the platform where you fight Hock means that there's a good chance he'll be able to fire at you from behind or the side while you're taking cover from the Eclipse mercs swarming the platform. Adding to this, your party for the Hock fight consists '''only''' of Shepard and Kasumi, since you can't take a third partymember to Bekenstein. It becomes pathetically easy after Kasumi uses some [[CutscenePowerToTheMax fancy acrobatics]] to permanently disable the gunship's shields, but to get to that point you have to survive several large waves of Eclipse mercs.
** Enyala, the boss of Miranda's loyalty mission. A relatively unimportant enemy who ends up being a nightmare, especially on higher difficulties. She fights with the rare and devastating Claymore shotgun and powerful biotic attacks, and has multiple layers of protection, as well as a large number of EliteMooks backing her up. What really makes her boss fight into a controller-thrower, though, is the layout of the area you fight her in. It's set up like the perimeter of a rectangle, with a walled pit in the center. She comes around one side, while her troops take the other, trying to catch you in a pincer. While ''Mass Effect 2'' usually gives you a good length of time to recover health and shields between volleys, this battle comes with a pretty strict time limit, because if you delay even a little, she and her mooks will surround your squad and make you die. Both she and her mooks are immune to crowd control abilities until their protection is stripped (and being elites, the mooks have protection even on lower difficulty levels), and there's a very good chance your squadmates will get taken out by her allies before you can finish her off, or vice versa.
** The bosses of Jack's and Grunt's recruitment missions. In Jack's, Warden Kuril has taken up residence behind a shield that has to have its emitters -- which are spread out across the field -- in a horrible snarled mess of a battlefield with awkwardly positioned waist-height walls and well-defended enemies who can come from virtually anywhere. In Grunt's, you need to deal with an YMIR mech, Jedore herself, and a seemingly endless chain of berserk, armoured krogan (there are actually only about four of them, but it feels like dozens -- especially given the krogan HealingFactor) who stroll forward firing shotguns at you and climb up onto the walkway you're on to flank you. Both of these are early enough in the game that you probably don't have high-level powers or all that many teammate options.
** The Oculus. Like the Praetorian, the Oculus will float towards you. Only thing is, all the tricks you once used to defeat Praetorians no longer work. There's no other mooks in the fight to Biotic Charge at (and away from the boss), it sees through Tactical Cloak, and it has a single monolithic armor bar (which is immense at that), so you can't DPS it into a recovery phase.
* ''VideoGame/MassEffect3'' contains an unintentional example: [[FanNickname Marauder Shields]], the last Marauder you meet in the game while [[spoiler:limping, wounded, to the Citadel transport beam in the finale]]. While normally a simple {{Mook}} -- and this encounter was ''intended'' as such -- in this section, you have only a pistol and no shields, so on Insanity difficulty, he may well become the toughest encounter in the game, killing you if you miss even once. The [[RevisedEnding Extended Cut]] significantly nerfs Marauder Shields's, well, shields, making the fight much easier.

** [[MonsterKnight Undyne]], the FinalBoss of Waterfall. No matter which route you take, she is likely to give you hell. ([[GoldenEnding True]]) PacifistRun? You fight her [[LowLevelRun with your starting HP]] and can't attack her while she showers you with barrages of magical spears that you can't dodge and instead have to [[UnexpectedGameplayChange block with a magical shield.]] The only way to defeat her without killing her is to [[spoiler:run away from the fight, then run until she inevitably catches up, and then repeat until she collapses from exhaustion, which is only hinted to even be possible, let alone required, by a single line of dialogue just before the fight -- and even then it can be only done when she changes her attack pattern for a few turns]]. She gets a bit easier on a Neutral Run, where you don't have to bother with the [[ThouShaltNotKill no killing rule]] before or during the fight, [[TheDeterminator but even after having 0 HP, she still fights on for a few rounds]] -- but then comes the [[KillThemAll Genocide Run]], where she seemingly turns into a {{Zero Effort|Boss}} CutsceneBoss... and then she becomes [[OneWingedAngel Undyne the Undying]], beating the crap out of the player with new, much faster, stronger and more random versions of her two regular attack patterns, with several new attacks thrown in. One way or another, defeating Undyne will take you a while.

** Asgore Dreemurr, the King of Monsters, on a Neutral-Pacifist run[[note]]Since you can't get the [[GoldenEnding True Pacifist]] ending on your first playthrough, this type of run is the best you can do at first, although it cuts a lot of work out of getting the GoldenEnding[[/note]]. Since he ''[[ButThouMust forces]]'' you to fight him[[labelnote:explanation]]He ''[[InterfaceScrew destroys the Mercy button]]''[[/labelnote]] and has lots of health and very damaging attacks [[LowLevelRun compared to your own low stats]], it'll take a long time before he goes down, especially if you're unused to using the FIGHT command (which you won't have used much, if at all, during a Neutral-Pacifist run), and his attacks are hard to dodge.

* The Steel Mechorilla from ''VideoGame/{{MOTHER 3}}''. Nothing gimmick-y about it -- it's just very, VERY powerful, powerful enough to beat up all your characters without the slightest difficulty. And it has a ton of HP. ''And'' he powers himself up if you [[spoiler:cast PK Thunder more than twice]], becoming even tougher (not helped by the fact that [[spoiler: Boney's EnemyScan ability tells you that it's weak to PK Thunder, but using that ability on it twice makes it go [[TurnsRed berserk]] and thus [[HoistByHisOwnPetard makes the fight even harder]]]]). It is not unheard of for a player to load all four characters' inventories with healing items... and end up using ''almost every single one.''
** The Barrier Trio, later in the game, are also a pain. They're a group of three stone guardians who completely [[NoSell negate]] all offensive PSI, and have devastating PSI of their own. Just for the final touch, when you're about to finish them, they throw the all-powerful PK Starstorm at you.

** Tressa, Chapter 3: [[spoiler:The Venomtooth Tiger, a vicious monster]]. The boss hits hard and can poison your party members. Later on in the fight, it uses a skill called Peerless Poison, which causes the poison to drain your SP and BP, in addition to your HP. If you're having trouble keeping up with the healing or dispelling poisons, it will quickly overwhelm you.

** The QuoteSource and FinalBoss of the [[KillEmAll Genocide Route]], [[spoiler:[[CrouchingMoronHiddenBadass Sans the Skeleton]]]], who decided to [[LetsGetDangerous take matters into his own hands]]. His attacks can only deal ScratchDamage and he himself is a OneHitPointWonder... thing is, said attacks ignore MercyInvincibility, making you recieve ''[[DeathOfAThousandCuts one hit point of damage per frame]]'', and each frame applies a stacking DamageOverTime effect as well. As for killing him in one hit -- it won't happen since he ''dodges your attacks.'' On top of this, his own attack patterns are ''gruelling''; he opens [[CombatPragmatist using one of his most powerful attacks before your first turn]] (meaning you can die before you even see the battle menu) and then starts throwing barrages of fast, hard-to-dodge attack patterns at you... and ''then'' he reveals he was ''holding back'' and starts [[ConfusionFu switching patterns mid-attack]], [[WeaponizedTeleportation teleporting the player into the way of his bullets]], and [[InterfaceScrew attacking the player during their own turn.]] The interesting thing about this boss is that everything about him is [[InvokedTrope purposefully designed]] to be as rage-inducing as possible. He ''knows'' about your ability to SAVE and LOAD and, by extension, that he can't actually beat you in a fair fight, as you'll just keep reloading until you finally get the upper hand. So instead he purposefully taunts you, breaks the rules, and generally tries to be as big of a pain in the ass as possible, all in the hopes of making you RageQuit.

* Text-based HGame ''Corruption of Champions'' has the Minotaur King, second foe of the FinalBoss [[BossRush Rush]]. He constantly make your [[SanityMeter Lust]] bar fill up during the fight, which put the fight on a strict timer (There are items to decrease your Lust, but you carry a limited supply of them, and taking too much of those also limits how many HealthPotion you can have), he inflicts an enormous amount of damage, can stagger you with each hit (which, if you're unlucky, means you can go a few turns without being able to do anything). All of those would make him an annoying luck-based boss as is, but you also need to beat him at least twice and, more probably ''four times'' [[labelnote:Explanation]]He is one of the very few enemies that can only be beaten by raising his own Lust to 100, but the first time you do this, it automatically goes back to 0 and you have to do it again. The two more times come from the fact that he has a great resistance to Lust attacks unless you bring his [=HP=] down to 0(At the start, his Lust will only rise by 1 for each action you take. Bringing his HP to 0 once means that further Lust attacks will make his meter rise by 5, and beating him up a second time makes his Lust rise by 10).[[/labelnote]]. Combine all of that and you have a boss that even characters would have ground their stats to the max will have to rely on luck to beat.