Godzilla (2010 Marvel Animated Universe)

Godzilla is a giant mutant dinosaur exposed to radiation and an enemy to the Avengers.

Origin
Godzilla was originally a type of dinosaur that survived for millions of years and got exposed to nuclear energy from the Lifestone. Because of the radiation mutating the dinosaur, he became the most destructive creature on Earth.

Appearances
The Avengers meet the titular monster in Marvel's Avengers vs Godzilla.