Prickly Slug Fossil.

Paleontologists discovered fossils of a slug-like creature covered with prickly armors that lived on the ocean floor about 500 million years ago:

Called Orthrozanclus reburrus, the new animal was about half the size of a potato bug (called a garden pill bug by some) and had a front shell and long spines covering its entire body with a border of shorter spines along the edges ...

http://www.livescience.com/animalworld/070301_hairy_bugs.html

See also: World's Strangest Dinosaur Names