History Characters / TheBindingOfIsaacFinalBosses

* HornedHumanoid SkullForAHead: He looks like an undead demon.

* AdaptationNameChange: In a fashion that also changes the identity of the character. In ''Antibirth'', she was known as the Witness and was implied to be an undead Mama Gurdy attacking Isaac after, well, witnessing him kill his mother. In ''Repentance'', instead she's known as "Mother", and now she is essentially the zombified husk of Mom in the aftermath of Isaac killing her with the assembled Knife.

!!!'''Voiced by:''' [[spoiler: Patty Allen-Scott (''The Binding of Isaac''), Carla Kihlstedt (''Rebirth'' onward)]]

* GuideDangIt: The only in-game hint you have to his existence is "The Angels await!" You're supposed to bomb the Angel statues in the Angel Rooms, prompting them to engage you; both will drop a piece of a Golden Key on defeat, and getting both pieces opens a Golden Door in the Chest/Dark Room that leads to Mega Satan.[[note]]The Golden Door also only appears once you have completed the key for the first time, which is a GuideDangIt in and of itself.[[/note]] Fortunately, completing the key also unlocks "Dad's Key" as a regular item, which can also be used on the Golden Door for future playthroughs [[note]]The "Get Out of Jail Free" card also works[[/note]].

* DamageSpongeBoss: Clocks in at a whopping '''10,000 HP''', though he mercifully doesn't have the same damage scaling that Hush and Ultra Greed do.[[note]]Well, technically, he ''does'', but the scaling resets every time he transforms, so his {{damage reduction}} is hardly even noticeable.[[/note]] Even so, he teleports all over the place, so expect to spend a ''long'' time trying to kill this thing.

* FlunkyBoss: Summons The Harbingers, the Super Sins, and fallen versions of the Angels. If you take too long on one of his phases, he starts summoning regular Sins… [[TheLastOfTheseIsNotLikeTheOthers and The Hollow]].

* BossRush: It Lives has the ability to spawn {{Degraded Boss}}es such as Monstro, Larry Jr., and Chub to fight you alongside the enemies.

* FlunkyBoss: Will summon enemies intermittently. It Lives ups the ante by spawning {{Degraded Boss}}es.

* BodyHorror: The way Mom's body parts move throughout the fight (such as both eyes appearing on opposite sides of the room while she tries to stomp on you) suggest an ability to contort herself in downright FREAKISH ways.
* BossBanter: ''ISAAAAAC!''

* EvilIsVisceral: Likely the reason her body parts are detailed and somewhat deformed.
* EvilLaugh: She belts out a downright WICKED sounding one every time she successfully damages Isaac.

* GameplayAndStoryIntegration: Using the Bible instantly defeats her in her boss fight.

* ActionMom: A villainous example. Giving birth to Isaac doesn't stop Mom from being a boss.
* AttackOfTheFiftyFootWhatever: Her boss fight.
* AxCrazy: Her goal is to kill her own son, and she doesn't sound too upset about it during the fight, what with the laughing and all.

* BodyHorror: The way Mom's body parts move throughout the fight (such as both eyes appearing on opposite sides of the room while she tries to stomp on you) suggest an ability to contort herself in rather… impossible ways.

* ClimaxBoss: While normally a DiscOneFinalBoss, she takes this role in a Beast route. Once you defeat her, find a way to teleport out of the boss room and get en route to your ending.
* DeathByIrony: Crushed by her own Bible!

* EvilLaugh: She lets out one every time she successfully damages Isaac.

* FinalBoss: In your first playthrough. She's nowhere near the TrueFinalBoss, though.

* {{Gonk}}: See that leg up above? That's all the proof you need.

* SkippableBoss: Provided you have the Bible on you by the time you reach her, and it's fully charged.
* SmallRoleBigImpact: As you unlock more of the game, Mom's role as a final boss becomes more and more pushed to the side. However, your actions after defeating her still determine the course that your run will take:

* TrueFinalBoss: Was initially this to Mom's FinalBoss. However, this is subverted by the Halloween update, and further subverted by ''Wrath of the Lamb'' and ''Rebirth'', to the point that it's no longer anywhere ''near'' the real final boss.

* TrueFinalBoss: He was the final boss of the game in the Halloween update, but this was trumped by ''Wrath of the Lamb'' and has just gotten further and further from the truth as more content has been added.

* VariableMix: The Beast's version of "Revelations 13:1" sounds more brutal and oppressive than the rest, with demonic chanting, heavy drums, harder guitar, and a sense of impending doom.

** Ultra Famine starts with a brutal-sounding guitar wailing throughout along with evil chanting in the background.
** Ultra Pestilence also has the guitar, but his version has elements of horror and dread mixed in.
** Ultra War drops the guitar in favor of [[DrumsOfWar oppressive drum beats and percussion.]]
** Ultra Death opts for something less heavy, but still intense, including OneWomanWail and PsychoStrings with violin. It also has what sounds like animalistic squealing and shrieking near the end.

* {{Superboss}}: In ''Four Souls'', Delirium is the only boss who doesn't grant a soul upon defeat, instead allowing the victor to gain two treasure cards. He is also one of the harder bosses despite being considered a "normal" one, having stats on par with with a Mega Boss (Satan, The Lamb, etc.) and giving other monsters a higher dice roll. ''Requiem'' somewhat rectifies this by putting him in said Mega[[note]]now called Epic[[/note]] Boss tier, though he still does not grant souls, but at least he now has Dogma to keep him company in that regard.

* RuleOfSymbolism: All of Delirium's unlocks on the Tainted characters except for Isaac [[note]]covered by the Soul of Isaac after [[SpeedrunReward clearing Boss Rush beating Hush]][[/note]], the Lost [[note]]covered by Sacred Orb after beating the Beast[[/note]], Eden [[note]]whos randomization-on-hit gimmick doesn't have a corresponding unlock[[/note]], and Keeper [[note]]covered by The Hanged Man? after beating Ultra Greedier[[/note]] are items that allow any other character to use one of their gimmicks. The implication, of course, is that if the game is a DyingDream, all the possible choices that can be made in a run don't matter, since it's all the same story of Isaac's suicide.

* ContractualBossImmunity: One of two enemies who aren't harmed at all by the [[OneHitKill Chaos Card]]. In fact, all it does is piss Delirium off. Plan C (kill everything then yourself three seconds later) ''does'' technically kill Delirium, but its death animation is so long that Isaac will die before Delirium does. There are three ways around it, though: playing as Lazarus thanks to his ability to resurrect in the current room[[note]]Lazarus' Rags on another character will work, but Lazarus [[KillSteal still gets the credit]][[/note]], Inner Child, which also grants the ability to resurrect in the current room (with the bonus of letting any character get the kill credit as long as they have that item), and Soul of Lazarus (normally kills and revives the character in the same room as themself on use, but is used automatically if they die from anything else). [[OneHitPointWonder Tainted Lost]] can also use Plan C with his own Birthright[[note]]An item unique for every character. For Tainted Lost, it grants an extra life that revives him in the same room and deals 200 damage to nearby enemies[[/note]].

* ContractualBossImmunity: One of two enemies who aren't harmed at all by the [[OneHitKill Chaos Card]]. In fact, all it does is piss Delirium off. Plan C (kill everything then yourself three seconds later) ''does'' technically kill Delirium, but its death animation is so long that Isaac will die before Delirium does. There are three ways around it, though: playing as Lazarus thanks to his ability to resurrect in the current room (Lazarus' Rags on another character will work, but Lazarus still gets the credit), Inner Child, which also grants the ability to resurrect in the current room (with the bonus of letting any character get the kill credit as long as they have that item), and Soul of Lazarus (normally kills and revives the character in the same room as themself on use, but is used automatically if they die from anything else). [[OneHitPointWonder Tainted Lost]] can also use Plan C with his own Birthright[[note]]An item unique for every character. For Tainted Lost, it grants an extra life that revives him in the same room and deals 200 damage to nearby enemies[[/note]].

* KevLard: Ultra Pestilence has high HP and he's [[FatBastard overweight]].

* BulletHell: ''Rebirth''[='=]s version shoots red tears nearly constantly throughout the whole fight, even when retreating to the back of the room. In Mausoleum and Gehenna, Mom's Heart gains much more intricate bullet pattern, achieving true danmaku.