There were some pretty strange creatures hanging out in ancient oceans around the Cambrian explosion, but this worm with legs is the creepiest. Paleontologist Simon Conway Morris, who discovered the unnerving creature’s fossils in the Canadian section of the Rocky Mountains in 1977, was so confounded by its unlikely shape he named the species Hallucigenia.

Until now, scientists were unsure of the worm’s placement in the planet’s genetic history. Finally, researchers at University of Cambridge have linked Hallucingenia to “modern-day velvet worms, a small group of animals also known as onychophorans, which live in tropical forests.”

Scientists have also discovered that the claws on its 7 or 8 pairs of legs are what later became the jaws of velvet worms. New Scientist explains:

“The peculiar claws of Hallucigenia are a smoking gun, and may even help to decipher other problematic Cambrian critters,” said Martin Smith, lead author of the research paper. “By deciphering ‘in-between’ fossils like Hallucigenia, we can determine how different animal groups built up their modern body plans.”

(Photo: Wikipedia)