Eunice aphroditois--bobbit worm (aquatic, predatory, polychaete worm. It as has one of, if not the, longest bodies among the polychaete worms – their average length is one metre, and specimens measuring a whopping three metres have been discovered in the waters of the Iberian Peninsula, Australia and Japan.)
The Bobbit worm, Eunice aphroditois, is a ferocious underwater predator. Armed with sharp teeth, it is known to attack with such speeds that its prey is sometimes sliced in half. Though they do vary in size, they have been recorded to grow up to nine feet tall.
The Bobbit Worm. In case you're thinking "tough for the fishes, but I've got nothing to worry about," these beasts can grow to three meters long and grab prey larger than themselves. Read more at http://www.iflscience.com/plants-and-animals/worm-will-haunt-your-nightmares#cUQAV8TVB4Cb1hlD.99