Probably my favorite paleontologist (if you can have such a thing) is the late Stephen Jay Gould, and my favorite book of his is Wonderful Life, where he discusses the truly weird and wonderful inhabitants of the Burgess Shale, a black shale fossil bed (Lagerstätte) named after Burgess Pass, close to where it was found, high up in the Canadian Rockies in Yoho National Park near the town of Field, British Columbia.
In that book I was introduced to such Cambrian-era wonders as the five-eyed Opabina, with an appendage sticking out of its head like the hose on a vacuum cleaner, and the deadly predator Anomalocaris, whose crushing jaws operated like the shutter of a camera. Both are pictured here , and an immensely cool website devoted to Anomalocaris can be found here (with animations of the swimming animal).
Well, meet Orthrozanclus reburrus, the latest weird beastie to be rescued from the stones of the Burgess. At about a centimeter in length, it was distantly related to present-day snails, earthworms and mollusks. Orthrozanclus reburrus would have spent its days grazing on seafloor bacterial growths (the mountains around Burgess Pass were once the bottom of an ocean), moving along on a snail-like foot, and any predator stupid enough to take a bite out of it would have ended up with a mouthful of spines.
Fittingly, one of Orthrozanclus discovers is Simon Conway Morris, who "starred" in Wonderful Life, and the specimens are housed in Canada's own Royal Ontario Museum (The ROM).
Here's a link to another article on the discovery, with a picture of the actual fossil.