A dinosaur with an abnormally large ass; also can be a name for an asshole or one who is being an asshole.
"Goddamn you are being a total assasaurus!"
by nunnya business April 22, 2008
A gay dinosaur.
The paleontologist unearthed a fossilized bone in the rectum of a dinosaur and realized he had discovered an Assasaurus
by Hogindas August 01, 2015