Hallucigenia sparsa is a small, worm-like creature from the Cambrian period, known for its bizarre appearance. It features spiky spines along its back and several pairs of tubular legs ending in claws. This prehistoric invertebrate lived in marine environments, playing a role in the early evolutionary history of arthropods.

Hallucigenia sparsa is an extinct species that is primarily known from the Burgess Shale, a fossil-bearing deposit in the Canadian Rockies of British Columbia. This deposit dates back to the middle Cambrian period, approximately 508 million years ago.

During the Cambrian period, the region that is now the Burgess Shale was located near the equator and submerged under a shallow tropical sea. The environmental conditions were characterized by warm temperatures and a marine environment with soft, muddy substrates.

Hallucigenia sparsa likely inhabited the benthic zone of the Cambrian sea floor, where it played a role in the marine ecosystem as a detritivore or scavenger. It is believed to have fed on organic material available on the sea floor, utilizing its spines for protection against predators and its unique appendages for locomotion and feeding.