This is a dinosaur whose head resembles that of a penis. It is basically a cross between an allosaurus and a penis.
by Mahnahmahnah March 16, 2004
A massive penis, bigger than a doppelganger. The actual length of the phallusaurus rex cannot be measured, but when a person sees one, they know it is one.
by JoelyBoy November 10, 2007
An extremly verile character whose sexual prowess is second to none. Usually possesses a brontosaurus-like phallus which is used to spread his seed. Commonly known as a Mr. Brown.
"Oh you are quite the Phallusaurus Sex. You sexual prowess in invigorating. You should plant your seed in my loins. We shall spawn."
by Chad Davis May 8, 2006