An adult electric eel can generate a charge capable of knocking a horse off its feet

This charge can be at least as powerful as 600 volts, which is about five times the capacity of a typical American wall socket! This power is generated by a group of around 6,000 specialized cells called electrocytes, which are able to store electricity like a battery. Despite their name and appearance, electric eels are not actually "eels" - they are more properly classified as a fish similar to carp or catfish! Human deaths from these creatures is actually quite infrequent, though multiple jolts can cause heart failure. The main risk when encountering this animal is drowning after being stunned by an electric shock.

Souce : NatGeo