"Moon Girl and Devil Dinosaur"and (Dinosaur and Godzilla/Monster Transformations & Reversions)

Two Marvel comics involving reptiles...

A scientific expeirment gone wrong causes a Tyrannosaurus Rex to become a human boy in Moon Girl and Devil Dinosaur #33:

And from New Avengers (Vol.4, # 09) the story "American Kaiju." The American military injects a soldier with a gamma-enhanced cocktail of mutant growth hormones and the serum used by the Lizard from Spider-Man comics. The result? An all-American Godzilla!

Alas, he's cured in the next issue: