Name: Loch Ness Monster aka Nessie

When I was a kid, I loved the idea of a prehistoric monster living in the modern world. Time and experience have not been kind to my dreams though, as the likelyhood of a prehistoric marine reptile living in a cold environment seems less possible than ever. Additionally, unless they evolved to perform live birth, Nessie and her ilk would have to beach to lay eggs, or surface for a long time for the process of live birth, which would make for far more sightings and a probable capture.

In his book The Loch, Steve Alten put forth the idea that Nessie is really a species of eel that migrates to the Loch to breed via a system of underwater caves (Alten also attributed the mysterious Bloop to the eels). The current Nessie is one that somehow got stuck, screwing up its biological timeclock and causing it to continue growing. The eels were semi-amphibious, as they could venture forth great distances on land to feast on unwary animals and humans.

This makes some sense, as the eels being migratory and aquatic keeps them from being spotted regularly. However, there's no reason to suspect that there's anything there at all, although I'm still secretly rooting for the plesiosaur.