Chameleos

From Monster Hunter - Wiki on Neoseeker

The Chameleos is a Chameleon-like monster that can be fought in the Swamp and Forest and Hills. It has the ability to blend in with its environment using special scales on its body which can reflect light in a way to render it completely invisible. The ability to literally vanish is controlled by the monster's tail, which cut off, severely affects it ability to become invisible. Hunter rumours suggest that Smoke Bombs enable the monster to reveal themselves when invisible.