A name coined for the dinosaur that appears at the end of the stage 'DinoDino Jungle' in Gamecube's "Mario Kart: Double Dash!" The Derpasaurus sticks his face across the bridge as you are karting across.
Player 1: "dude, the derpasaurus rexknocked me off of the bridge!!! "
the words gump and tyrannosaurus rex put together. to be gumpy means to look stupid or really goofy or lame. a tyrannosaurus rex is the gumpiest dinosaur ever. so when you call someone a gumpasaurus rex you are saying that they are far beyond being gumpy.
mike: look at josh over there, hes such a weirdo.
sam: wow he looks really goofy, call him over here.
mike: hey you, gumpasaurus rex, come over here!
Someone or something that bites your ankles.
To a postman, an ankle biter is often known as a dog.
To an adult, an ankle biter may be a toddler.
To hikers, an ankle biter is sometimes a tick.
And so on.