In Marvel Comics, the planet-sized devourer of worlds is Galactus.
Galactus was created by writer Stan Lee and artist Jack Kirby and first appeared in Fantastic Four #48 in 1966. He is not simply an unusually large alien: Galactus is a cosmic entity who must consume the life energy of inhabited planets to sustain himself. His arrival is often treated as a universe-level threat rather than an ordinary supervillain attack.
Galactus is closely associated with the Silver Surfer, who originally served as his herald. The character’s scale and cosmic role distinguish him from Thanos, another major Marvel antagonist, who seeks power through the Infinity Stones. Galactus also has a different function from abstract entities such as Eternity, which represents the universe itself.
Although stories sometimes depict Galactus as destructive, Marvel narratives frequently present him as part of the universe’s natural cosmic balance. His signature armor-like appearance and enormous size have made him one of the most recognizable figures in superhero comics.