gumpasaurus rex
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!
sam: wow he looks really goofy, call him over here.
mike: hey you, gumpasaurus rex, come over here!