These tiny, barrel-shaped unicellular organisms called Coleps are feasting on the body of a crustacean larva in real time. . Coleps are single-celled organisms with a rigid, barrel-shaped body covered in calcium carbonate plates integrated into their cell. This armor functions almost like an exoskeleton, protecting them from hungry mouths. . Coleps are extremely common in ponds and lakes, and they behave like piranhas. When an organism is injured, the damage releases chemical signals into the wa