Chameleos

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 and Horn, which when cut off, severely affect its ability to become invisible. Hunter rumours suggest that Smoke Bombs enable the monster to reveal itself when invisible.