What’s something that would slowly eat away a planet?

[Dinosaursandanime65]

Like some kind of celestial virus

[NathanDavis]

" Grey goo is a hypothetical global catastrophic scenario involving molecular nanotechnology in which out-of-control self-replicating machines consume all biomass on Earth while building more of themselves, an scenario that has been called Ecophagy (the literal consumption of the ecosystem). The original idea assumed machines were designed to have this capability, while popularizations have assumed that machines might somehow gain this capability by accident.

Self-replicating machines of the macroscopic variety were originally described by mathematician John von Neumann, and are sometimes referred to as von Neumann machines or clanking replicators. The term grey goo was coined by nanotechnology pioneer K. Eric Drexler in his 1986 book Engines of Creation. In 2004, he stated "I wish I had never used the term 'grey goo'." Engines of Creation mentions "grey goo" as a thought experiment in two paragraphs and a note, while the popularized idea of grey goo was first publicized in a mass-circulation magazine, Omni, in November 1986 "

[MCheetah]

Humanity.

Or, if you want to go more sci-fi, bio-organic nanobots.

[Guy13]

Trials snd tribulations preceding the Second Coming of Messiah Jesus

[exitseven]

Humans.

[Dinosaursandanime65]

Oh yeah that definitely happens, then they go to another planet and start killing that one. One of the Gendaruses eliminates all of them and that planet is saved

[Dinosaursandanime65]

In THIS case however, three or 6 other Gendaruses on a different world clashed and made a nuclear… radioactive energy virus thing that slowly grew and consumed that world. Right now it is dubbed “Dinosaur Planet”