At rest, this fiendish creature resembles the crocodile, alligator, caiman or gharial it once was, though abnormally large with pupil-less white eyes and a curious acidic odor. When ready to hunt, it undergoes accelerated metamophosis into a more sophisticated form. Strong and fast, the fully transformed Crocodemon tears its way through barriers in search of nourishment, secreting an acid from its claws to even rip apart metal.
I used a Ghavial and the Rancor creature as a (somewhat too obvious?) reference, but it came out looking like some kind of Hunter from Resident Evil, which I didn't even think about. I don't think it looks enough like one to be a problem, though.