Despite their serpentine appearance, electric eels are not actually eels. Their scientific classification is closer to carp and catfish.
Their bodies contain electric organs with about 6,000 specialized cells called electrocytes that store power like tiny batteries. When threatened or attacking prey, these cells will discharge simultaneously, emitting a burst of at least 600 volts, five times the power of a standard U.S. wall socket.
The shock of an electric eel has been known to knock a horse off its feet.