A real big dog, a bloke who definitely hits the gym (among other things). Can also be used to describe anything that is abnormally large in comparison to it's average height (e.g. a Barge could be called a "BigPuppy").
When that one national powerlifter in your rowing team takes his shirt off for the boys:
Ruler of Lake Titicaca. Rumored to have a bunghole that gets very angry if it does not receive toilet paper. Cornholio the Great is often seen walking around with his shirt over his head and his hands in the air, chanting songs about his power, and his bunghole.
"I am Cornholio! You do not want to face the wrath of my bunghole, for I need TP!"
Butthead: Shut up, Beavis! (uh huh huh huh)
Beavis: Um, okay. (heh heh heh heh).