A slow-moving, bottom-dwelling ray (family Torpedinidae) that has a round body and short tail fin, and a pair of organs derived from modified muscle cells that are capable of delivering an electric shock to anything contacting them. The shock is used to stun prey, but can be painful to anyone treading on the fish. The largest species, the Atlantic torpedo (Tetronarce nobiliana), is 1.8 m long and can deliver 220 volts. There are two genera of 22 species found worldwide.