The electric eel has thousands of electric cells, with those organs making up four-fifths of its body. It lives in the Amazon River and its tributaries and is the most shocking animal on Earth; no other animal packs such a big charge. If attacking a large prey, a 9-foot-long eel can discharge about 800 volts. One zap could easily stun a human senseless. The larger the eel, the bigger the charge. The electric eel’s shocking power is so great that it can overtake its victims while 15 feet away.