The Cleaver
The cleaver, seemingly able to be used not only as a kitchen tool but also as a medieval weapon and a possibly mirror for personal grooming (although that's not really recommended). It's a hefty knife with a lot of power behind it.
A cleaver is thick and doesn't usually have the super-sharp edge that other knives do, this is due to the rigors that they go through during use. Cleavers are used to chop through bone and thus need a lot of weight behind them plus, a razor-sharp edge would only degrade quickly.
Another form of the cleaver you see sometimes is the chinese cleaver, this style is similar in shape to the standard western bone cleaver but is thinner and lighter. It is often used as a variation on the chef's knife for vegetables and boneless meats and as a spatula for moving your chopped up food.