Real Creature

[BoxingGorilla]

I'd think the E.T. (my vote) and his people are the most likely. Of the earth bound creatures I would say Mbembe and then the Loch/Lake monsters.

Anything that can submerge and hide in the murky depths is going to be hard to find. And who wants to go stumping around the Congo looking for Mbenbe? Not this white boy.