Hallucigenia

Hallucigenia is an extinct genus of animal found as fossils in the Middle Cambrian Burgess Shale formation of British Columbia, Canada. Another species is found in the Lower Cambrian Maotianshan shale of China. 
"Hallucigenia" was thought by Stephen Jay Gould to be unrelated to any living species, but most palaeontologists now believe that the species was a velvet worm, a relative of modern arthropods.
Unlike its contemporary "Aysheaia", "Hallucigenia" has very little resemblance to modern Onychophora. The elongated, and clawed legs bear little resemblance to the paired annulated legs of the Onychophora. It is unknown what the spines were made of and how much 'protection' they offered. It is not easy to explain why 30 or more specimens — each thought to have seven pairs of rather long, flexible legs — do not show even one example of paired legs. But at least this reconstruction of the animal can plausibly walk, and the spines serve a reasonable purpose. A picture of this reconstruction as well as a photograph of an actual fossil can be seen on the Geological Survey of Canada's website.