Tonberry

The Tonberry is a diminuitive amphibious humanoid monster from the Final Fantasy video game franchise. First appearing in Final Fantasy V, it has returned in numerous games since. It is considered to be one of the most insidious creatures in the series.

Overview
Tonberries appear to be squat, bipedal reptiles or amphibians with green skin and small yellow eyes. They dress in hooded robes and are always seen to be carrying a lantern and a knife. Tonberries don't appear very threatening and are often misconceived as being puny, but quite the opposite is true. In most of their appearances, they move very slowly and take several turns to perform an action against the player's party, and while they may look feeble, they can take an astonishing amount of damage for non-boss creatures. What Tonberries tend to do is after a certain amount of time and after taking so many hits, they suddenly strike with their knives and kill the player instantly.