mathasaurus rex 

one who likes to shriek and growl when sexually excited by math problems, sometimes waving their arms in a dinosaur-like fashion.

when jimmy began to grunt as he started the math test, there was no doubt he was a mathasaurus rex.

mathasaurus rex by winerschnitzal111 June 9, 2010

Methasaurus Rex 

term given to sketchy meth-heads in or around a city

Its about 10 til, we are driving to Carl's Jr. And we see a Methasaurus Rex, barefooted as fuck! Welcome to Redding, CA.

Methasaurus Rex by ericd000e August 31, 2010

Manthasaurus Rex 

An very old gay man (70+) who is on the prowl for younger gay men (20-50) in the hopes of bedding them in exchange for lots of free drinks, food, and attention. Flashes Ben Franklins and wears an expensive watch and ring.

Well, tonight is totally dead, except for that Manthasaurus Rex in the corner gawking at you.

Manthasaurus Rex by silverdoggy March 31, 2012

Methasaurus Rex 

A meth user that has gone zombie from using too much meth for too long and who no longer needs food or sleep because they run on amphetamines and nuclear brain fuel.

The Methasaurus Rex went berserk when the drug dealer told them there were no drugs and ripped the fender off the dealer's car.

Methasaurus Rex by Jamiesaurus March 11, 2021