History Main / PerpetualMotionMonster

* The Angels in ''NeonGenesisEvangelion'' are explicitly stated to have an infinite power source in their bodies: the S2 Organ. Therefore, while alive, they have no need for sustenance, rest, etc. and are effectively immortal, though they can still be killed if damaged enough.

* ''DwarfFortress'' actually has tags for these including [NOEXERT], [NO_EAT], [NO_DRINK], and [NO_SLEEP]. In-organic creatures like bronze colossi and iron men don't need any, while Goblins just don't need to eat or drink.

* The God Tiers in ''{{Homestuck}}'' are likely this. A player who reaches god tier can only die a heroic or just death. Death by starvation/thirst probably doesn't count.

* Not "monsters" per se, but ''{{Discworld}}'' {{Golem}}s just keep going and going and going and going. They're used for menial, tedious labor typically, since they don't have to sleep and, for the most part, enjoy it as much as they can enjoy anything. They even use this as a form of passive-aggressive protest via LiteralGenie; they're smart enough to take initiative and can read the intent behind orders, but if you mistreat them, they're liable to fight back by doing ''exactly'' what you say, constantly, until someone figures it out and tells them to stop. This can mean that the golem you asked to "pump some water" doesn't stop until your shop's street is partly underwater.

* The Jem Hadar in ''StarTrekDeepSpaceNine'' are genetically engineered so that the only source of nourishment they need is [[{{Phlebotinum}} Ketracel White]], a narcotic which keeps them loyal and without which they die after going violently insane. On top of that, they are conditioned to be unwaveringly loyal (though this has proven to be slightly unreliable, hence the White as a secondary measure).

This is a type of monster that is immune to starvation and dehydration, it may not even [[TheInsomniac have to sleep]] or breathe. Much like the Energizer Bunny, it just keeps going and going and going. Perpetual Motion Monsters are either explicitly supernatural, a set super advanced MechaMooks, or [[{{Magitek}} both.]]

Science savvy characters may [[DiscussedTrope discuss]] how implausible it is that the walking dead in a ZombieApocalypse, despite craving brains, can keep walking 24/7 for years or longer without any kind of sustenance. Compounded by that fact that though decayed they [[SlidingScaleOfUndeadRegeneration never actually rot enough to stop posing a threat.]] Frequently, TheProfessor / MadScientist will fear (or marvel) at [[JustThinkOfThePotential the potential]] these thermodynamic law breaking monsters represent. This is the whole idea behind undead armies in any setting-- they are weak but fearless and while slow, they can march 24/7 with no supply lines, all while [[TheVirus assimilating the enemies' fallen]].

It's worth noting that a character with the right type of {{Immortality}} who eats and drinks can still be a Perpetual Motion Monster-- or rather, a Perpetual Motion '''''Man.''''' Their form of immortality specifically preventing them from dying due to starvation and dehydration ([[ImmortalityHurts though they probably won't enjoy it]]). Such a character can make for a truly ImplacableMan-- nothing can keep him from his goal, not even the ravages of time!

For extra threat, the Perpetual Motion Monster is also usually unaffected by dismemberment (except for the "annoyance" of a lost limb, though a [[AppendageAssimilation needle and thread can solve that]]). For extra ''extra'' threat, it's also a SuperPersistentPredator; since being a Perpetual Motion Monster means it doesn't actually need to eat except for the pleasure of it, it can afford to go to the ends of the Earth in pursuit of that one tasty hero-sized morsel.

Compare AutomatonHorses (not the [[MechanicalHorse mechanical variety]]), where this is noted as one of the features that make fictional horses unusual. Compare ForgotToFeedTheMonster when this is averted.

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!!Examples:

[[AC:{{Anime}} and {{Manga}}]]
* The [[ArtificialHuman synthetic humans]] in ''{{Biomega}}'' come pretty darn close. They can live for months without food and for weeks without water and not lose efficiency.

* [[OurVampiresAreDifferent Chiropterans]] in ''BloodPlus'' won't die from starvation, as happened to one imprisoned in a concrete block in Russia. It was emaciated but still awake and capable of killing.

[[AC:{{Comics}}]]
* [[FantasticFour Reed Richards]] in ''MarvelZombies'' cites this trope as his justification for believing the zombie plague is the next step in evolution. He then proceeds to [[spoiler:infect the rest of the Fantastic Four.]] In this case, [[ReedRichardsIsUseless Reed Richards is]] [[EvilutionaryBiologist Genocidal]].
* [[DisneyDucksComicUniverse Scrooge McDuck]] once had an immortal zombie go after him for very long time, often walking nonstop across oceans, being frozen in ice for long time, and so on.
* The zombies in ''TheWalkingDead'' are very much Perpetual Motion Monsters.

* The monster from the movie version of ''PeterBenchleysCreature'' survived locked in a cage on the sea floor without any food or room to move for decades without any debilitating effects. The book version averts this by having it stalk out of its cage in a deep sea trench ever so occasionally.

[[AC:{{Literature}}]]
* In RobertEHoward's ConanTheBarbarian story ''Literature/BlackColossus'' there's a giant venomous python which slithers out of a ''3000 years old tomb'' and is still lively and in top shape.

* In ''TheZombieSurvivalGuide'' zombies are explained by the virus which creates them replacing their mitochondria and taking over respiratory functions so they no longer need to eat or breath ([[HandWave ...somehow]]) and slightly more plausibly, delaying decomposition by protecting the body from rotting as the immune system would have. The later part of the trope is also averted, since zombies do rot away after a few years, unless they're in arid environments or end up being frozen.

[[AC:LiveActionTV]]

[[AC:{{Mythology}}]]
* The serpent that guarded the GoldenFleece, which never slept or left the tree except when drugged.

[[AC:TabletopGames]]
* Constructs in ''DungeonsAndDragons'', such as golems.

* Artifacts in ''MagicTheGathering'' usually have this quality, as do a lot of undead. Phyrexians in particular are prone to combining the two.

[[AC:VideoGames]]
* Necromorphs in ''Franchise/DeadSpace'' don't need to eat, drink, sleep, or breathe. Have fun!

[[AC:WebComics]]

--> -- '''{{Hellboy}} II: The Golden Army'''

* Willy Pete from ''{{Empowered}}'' is an incredibly powerful fire elemental that eats superhuman flesh because he likes the taste, and because super-strong flesh is the only food that his mouth won't instantly incinerate. Being a fire elemental, he doesn't actually need to eat.

* The eponymous army in ''Film/{{Hellboy}} And The Golden Army'' is a positively inhuman combination of perpetual motion monster, TheJuggernaut, and ''[[PullingThemselvesTogether regenerating]].'' It was an ancient weapon GoneHorriblyRight to the point the elf king who commissioned it sued for peace after it massacred a human army.

--> -- '''{{Hellboy}} And The Golden Army'''

* The [[OurTitansAreDifferent Titans]] from ShingekiNoKyojin. While lack of sunlight and fatigue can slow them down, they do not age, sleep, or thirst and do not need the human flesh they eat [[hottip:*:They lack digestive tracks beyond their stomachs and just regurgitate when full]]. They even regenerate biomass instantly and out of nowhere while thriving.

* Necromorphs in ''DeadSpace'' don't need to eat, drink, sleep, or breathe. Have fun!

* In the ConanTheBarbarian story ''Black Colossus'' there's a giant venomous python which slithers out of a ''3000 years old tomb'' and is still lively and in top shape.

* Not "monsters" per se, but ''{{Discworld}}'' {{Golem}}s just keep going and going and going and going. They're used for menial, tedious labor typically, since they don't have to sleep and, for the most part, enjoy it as much as they can enjoy anything. They push it UpToEleven as a form of protest in one book, where they refuse to ''stop'' working.

* The Jem Hadar in ''StarTrekDeepSpaceNine'' are like this; although with some {{Phlebotinum}} required mostly to maintain their unyielding obesience to the Founders and the Vorta. They die without it so it might be nutrients, but it also is implied that their minds are crafted such that they cannot live without this control.

* Necromorphs in ''DeadSpace'' don't need to eat, drink, sleep, or breathe in a vacuum. Have fun!

* The Uncroaked/decrypted in ''{{Erfworld}}'' have zero upkeep.

This is a type of monster that is immune to starvation and dehydration, it may not even [[TheInsomniac have to sleep]] or breathe. Much like the Energizer Bunny, it just keeps going and going. Perpetual Motion Monsters are either explicitly supernatural, a set super advanced MechaMooks, or [[{{Magitek}} both.]]

** Taken to an interesting new height in Fear Itself. While possessed, he truly becomes unstoppable. At some point in the event, he calmly walks to San Franciso from a dozen miles away, while the X-men try a [[CrazyPrepared bajillion]] plans to stop him. Teleporting him away does nothing, he just reappears instantly. Digging a giant trench in front of him does nothing, somehow he strolls calmly across thin air!

* In ''TheLordOfTheRings'' there's the Watcher in the Water, a massive squid-like beast living in the pool of water just outside Moria. Apparently, being there for centuries didn't affect his strength, seen when it attacks the Fellowship.
** Actually it was stated that it had been driven from the deeps of Moria into the flooded valley as a guardian and to trap the dwarves inside Moria. A creature that big just hanging around in caves needs to have SOME of this going on though.
* In ''TheZombieSurvivalGuide'' this is explained by the virus which creates zombies replacing their mitrocondria and taking over respiratory functions so they no longer need to eat or breath ([[YouFailBiologyForever ...somehow]]) and slightly more plausably, delaying decomposition by protecting the body from rotting as the immune system would have. The later part of the trope is also averted, since zombies do rot away after a few years, unless they're in arid environments or end up being [[SealedEvilInACan frozen]].

* The Jem Hadar in ''StarTrekDeepSpaceNine'' are like this; although with some {{Phlebotinum}} dependency.
** Not really. Take away their Phlebotinum and they go crazy and die fairly soon, much the same as when you take away a human's food and water. At least one episode revolved around this, and one of {{The Federation}}'s major war strategies was to destroy the Ketrasel White storage facilities.

* The [[GattacaBabies synthetic humans]] in ''{{Biomega}}'' come pretty darn close. They can live for months without food and for weeks without water and not lose efficiency.

* The [[OurGiantsAreBigger Titans]] from ShingekiNoKyojin. While lack of sunlight and fatigue can slow them down, they do not age, sleep, or thirst and do not need the human flesh they eat [[hottip:*:They lack digestive tracks beyond their stomachs and just regurgitate when full]]. They even regenerate biomass instantly and out of nowhere while thriving.

* The Jem Hadar in ''StarTrekDeepSpaceNine'' are like this; although with some {{Phlebotinum}} dependency.

* The [[InSeriesNickname titular]] warriors in ''{{Claymore}}'' do not need to eat or drink except in small doses. Though, when they awaken, they eat human flesh regularly, but can go without for a long time (several years), but it does weaken them...

* The titular army in ''Film/{{Hellboy}} And The Golden Army'' is a positively inhuman combination of perpetual motion monster, TheJuggernaut, and ''[[PullingThemselvesTogether regenerating]].'' It was an ancient weapon GoneHorriblyRight to the point the elf king who commissioned it sued for peace after it massacred a human army.

* The original ''{{Terminator}}'' movie made the titular cyborg sound like this trope, until the second film subverted it by revealing that his power cell would eventually run out....after 120 years.

* [[ScroogeMcDuckUniverse Scrooge McDuck]] once had an immortal zombie go after him for very long time, often walking nonstop across oceans, being frozen in ice for long time, and so on.