The gulf toadfish, like some of the other fish on this list, has slimy, scaleless skin, a large, flat head and a wide mouth with sharp teeth. And it is ugly for a purpose — by looking disgusting, it avoids capture and predation. Don’t want to be deceived by appearances? Well, in the case of the gulf toadfish, it is best to stay away from it, since its slime actually has toxins that can irritate skin.