hidden monster 

its when u r having sex with a pregnant woman and the baby insde her gives u head

i dont no an examlple

hidden monster by john December 6, 2003

Hidden Monster 

A large piece of shit that gets covered up by the seat cover (behind the toilet); the turd is partially visible through the thin white paper

That hidden monster is gross looking and stinks.
Did you see the hidden monster in the toilet at Burger King?
Fuck! It's a hidden monster!

Hidden Monster by THIS-IS-STUPID November 16, 2010