Godzilla Gurn 

A term used to describe a particular and severe gurn (a distorted facial expression, caused by various drugs, resulting in a grotesque face and in some cases, the jaw action of a jackhammer).

An individual displaying a savage 'Godzilla Gurn' may almost appear to be a dinosaur, due to his or her display of ferocious jaw power, locked facial expression and huge glaring eyes. Unlike a normal gurn where the jaw is contorted into numerous positions, 'Godzilla Gurn' subjects appear to have fixed clamped jaws.

1. "Blimey! That chap has a vicious godzilla gurn."
2. "Watch out! Here comes gurnzilla."

Godzilla Gurn by The Crimson Adder July 2, 2009