Two centimeters tall, with giant thorns sticking out from its body. Hallucigenia has been described one of the most bizarre animals that ever lived in the sea.

The remains of an ancient worm species called ‘Hallucigenia’ were so bizarre looking that scientists originally reconstructed it upside down and back to front. Now Martin Smith reveals the most complete picture so far of this peculiar marine worm.

Read the Nature paper ‘Hallucigenia’s head and the pharyngeal armature of early ecdysozoans’ at­4573

Find out more about Hallucigenia and other finds from the Burgess Shale at