For this type of being, sustenance goes well beyond organic matter—or any kind of matter, for that matter. More dangerous than Alien Locusts and those who feed on blood, Life Energy, or planets, what it eats does not even exist tangibly, for it feeds on existence itself. Such individuals often are Eldritch Abominations or display The Power of the Void.
See also Reality Warper, which is about controlling reality instead of eating it, Abstract Eater which is the super trope to this, and Clock Roaches which are guardians of causality that eliminate things that threaten it. The eaters' feeding habit may cause Ret Gone.
- Dragon Ball Super: At the end of the Future Trunks Saga, the Big Bad's spirit somehow possesses The Multiverse itself, creating an Ax-Crazy Genius Loci — and forcing Goku to Summon Bigger Fish in the form of a certain Top God.
- Shakugan no Shana: The Denizens of the Crimson World are monsters from another world who consume the "power of existence" of humans. If they eat your power of existence, you're Ret Gone'd from reality. Interestingly, the majority of the cast are such monsters, and a significant number of them try to find a way to get around their morally-indefensible diet. They eventually find a way, thanks to Snake!Yuuji.
- Edens Zero: The Chronophage is an Eldritch Abomination that feasts on the time of planets, which reverts them to an earlier state depending on how much time is eaten, ranging from decades to millennia. This essentially overwrites a planet's present existence and history with its own past, creating a sort of pocket Alternate Timeline. What's more is that those who manage to escape the planet will not only avoid getting overwritten themselves, but also won't be affected by whatever changes may occur to their past selves, thus allowing two versions of the same people to co-exist free of any Temporal Paradoxes. Conversely, anyone left behind who wasn't there in the past will be erased from existence.
- From Big Finish Doctor Who the Neverpeople, who consume time, erasing people from existence and almost destroying the Web of Time. Then Zagreus, the personification of Anti-Time, who could destroy the Universe if released.
- The Time Machine has the Creevix, Insectoid Aliens who are the masters of time from the next universe along. They consume potential future and in an Alternate Timeline consumed the Universe after entering on 23 November 2013. With a massive Timey-Wimey Ball the Eleventh Doctor influences his previous selves to stop their plan.
- The Anti-Monitor of The DCU destroys and absorbs the energies of many universes to become stronger. The instability of the few universes eventually causes the creation of the pre-New 52 New Earth.
- Shazam: Mister Mind almost became this in 52, bringing the 52 alternate universes in existence (their main differences being the parts of the respective realities which he "ate").
- All-Star Superman had the Chronovore, a monster that eats time. When it feeds, the surrounding environment and creatures suffer Rapid Aging.
- While Unicron appears to be a "mere" Planet Eater, he actually feeds off of existence itself in his bid to eliminate all of reality and be truly alone. The dark god has already devoured more than a fifth of the multiverse. He actually managed to devour all creation once, but it grew back while he slept.
- A motif in the latter half of Seconds is that falling snow takes the appearance of consuming the fabric of the current reality.
- Black Queen, Red King has one in the form of Oblivion. Discord claims that Oblivion was created to consume all of reality itself.
- In Pony POV Series, Makarov absorbs other beings, which causes them to be Ret Goned. The author describes him as an "Existence Vampire".
- In the Harry Potter fanfic King Of Kings Ruling Over Rulers, Ayavan is capable of consuming the timeline of living beings.
- In the Magical Girl Crisis Crossover Shattered Skies: The Morning Lights, Joker unleashes one of these upon the Precure universe. "The entity" consumes and ret-gones every Precure continuity after Go Princess, and manages to consume all possible futures from the remaining ten continuities before it's finally stopped. It leaves a catastrophic Time Crash in its wake.
- The Neverending Story. The Nothing is consuming the land of Fantasia. If it isn't stopped, Fantasia will be destroyed.
- The Atrocity Archive has an infovore, an extrauniversal intelligence that feeds on quantum information, causing the Alternate Universe it was summoned into to gradually collapse.
- "The Space Eaters" by Frank Belknap Long begins with a conversation between the narrator and his friend on such Eldritch Abominations:
"Suppose there were a greater horror? Suppose evil things from some other universe should decide to invade this one? Suppose we couldn't see them? Suppose we couldn't feel them? Suppose they were of a color unknown on Earth, or rather, of an appearance that was without color?... What could we do? Our hands would be tied. You cannot oppose what you cannot see or feel. You cannot oppose the thousand-dimensional. Suppose they should eat their way to us through space!"
- Stephen King's The Langoliers had an airliner fly through a "time rip", landing at an airport with all its passengers but ten disappeared. The ten passengers, who were all sleeping during the passage through the rift, were all stuck in time such that time did not move forward (although they could move within that frame). Eventually, they saw mysterious ball-like creatures with sharp gnashing teeth literally "eating" the surrounding existence itself, approaching them....
- In Discworld, the Things from the Dungeon Dimensions want to invade the Disc because their home is sorely lacking in reality. They believe invading the Disc and consuming its reality will make them more real, though it's stated to be as futile as the ocean trying to warm itself with a candle.
- In City at the End of Time by Greg Bear, the Typhon manifests as this at the end of time, untold trillions of years in the future. The Typhon eats away at the logic of the universe; within it, nothing makes sense, and the rules of nature no longer apply. The last city in existence, the Kalpa, only just barely holds the Typhon at bay with its reality generators, and they have slowly been failing.
- Magic: The Gathering:
- The Eldrazi titans were exactly this before being trapped in a physical form on the plane of Zendikar by three powerful planeswalkers. Now they simply nom Zendikar from the inside, turning everything they meet to dust.
- While each variety of atog has its own diet, the chronatog is the most bizarre and is described as feeding on time... somehow. In the card game this is represented by the player skipping his next turn.
- Mage: The Awakening: The Abyss as a whole constantly gnaws at reality, for it is anti-reality made manifest, a realm of contradiction, paradox and negation opposed to existence as we know it.
- Unicron from the Transformers eats universes. In every continuity he's the same individual, at some different point in his existence. Some universes he devours, others are saved from him, and he's shunted to the next one to begin the cycle anew. According to the Transtech Cybertronians, Unicron has succesfully terminated 1,176,325 universes so far (out of 15,962,782 catalogued by them).
- Bonus Boss Culex in Super Mario RPG claims to be this, in his Badass Boast.
I am matter... I am antimatter... I can see your past... I can see your future... I consume time... And I will consume you!
- Grey Goo (2015) has The Silence. Little is known about it- but it's capable of consuming literally everything it touches and leaving behind nothing but darkness. That black mass of empty space in the sky at night where there's a gap in the stars? That's The Silence. It eats light, sound, and, well, pretty much everything.
- Chrono Cross has the Time Devourer, the main antagonist of the game and the fusion of Lavos and Schala from the previous game.
- Sonic the Hedgehog has two:
- From Sonic the Hedgehog (2006), there's the god of time and light Solaris, who plans to devour all of existence.
- Sonic Generations has the Time Eater, a creature that eats holes in space and time and throws Sonic into places he's been to before (and one which he hasn't and probably shouldn't be able to). It turns out that it's an Energy Being that Eggman and his past self turned into a cyborg-mech-abomination.
- Marathon Infinity has W'rkncacnter, who as soon as it escapes from its prison in the sun screws with reality just by existing, and THEN it starts eating.
- The Elder Scrolls V: Skyrim: Alduin the World-Eater, whose raison d'etre is to devour the universe at the end of time to make way for the next world. In the current one, according to some theories he jumped the gun: it wasn't time for the world to end, which was why first the Tongues, then the Dragonborn were able to defeat him. He also seems less interested in destroying the universe and more interested in ruling it.
- Neo-Exdeath from Final Fantasy V declares its intent to consume all memories, dimensions, and existence, so that it too will disappear, forever.
- The Maelstrom, a force of pure chaos and destruction itself, from LEGO Universe.
- In the FreeSpace 2 mod Blue Planet, overheard thoughts of Sufficiently Advanced Aliens reference something they call an "ontovore". The word's etymology suggests that it refers to something which consumes existence. They also refer to the same thing as an "acatalepsis event". Not a whole lot is known about it, and it's implied that even thinking about the subject is dangerous to one's mental health.
- In Tasty Planet, in the last level you eat "Time Itself". When even this is eaten and there's absolutely nothing left, you implode and become the next Big Bang.
- In Undertale, this is revealed to be YOU. More specifically, the effect the player has on the world by saving and loading their game.
Sans: Our reports showed a massive anomaly in the spacetime continuum. Timelines jumping left and right, stopping and starting ... until suddenly, everything ends. Heh heh heh That's your fault, isn't it?
- League of Legends has the non-canon "Dark Star" skins for several champions that are built off this concept, turning them into Cosmic Entities who annihilate and feast off entire galaxies at a time. The line is codified by Dark Star Thresh, an Anthropomorphic Personification of a black hole who believes time is a cog in a dying machine, and is already responsible for the cessation of multiple realities by the time he hits Runeterra.
- Black Holes, while not alive, are so dense and massive that spacetime itself is distorted in an infinite curvature, resulting in a gravitational pull that consumes everything, even light.
- In such a place, gravity is so strong that several laws of physics are either bent or outright broken. It's not entirely inaccurate to call them holes in reality itself.
- A Vacuum metastability event, also not alive, would fit the bill quite well too. The thing would expand at the speed of light devouring the entire Universe and once within it changing the laws of physics and the physical constants... just to have everything collapsing inmediately in a gravitational singularity.