Behold, a crocodile. The only thing that they have to worry about is hunger when they cannot catch a meal, and camouflage that is better than the eyes of their prey. What if a species of mushroom started growing on their skins in a symbiotic relationship. The fungus provides camouflage and the croc provides a meal. If enough radiation were induced to fuse the two entities together, could the croc have offspring born with mushrooms? And is this plausible at all? Thanks!
EDIT: Maybe check out the Mesodinium chamaeleon? It’s part plant part animal.