What is "echmatocrinus"

Echmatocrinus is a problematic Cambrian animal which resembles a crinoid or an octocoral. It is known only from the Burgess shale.

The creature was a little like an inverted cone, with a crown of seven to nine tentacles. Each tentacle was covered with small extensions. The cone itself was covered with irregularly arranged mineralised plates. The organisms lived a solitary lifestyle, although juveniles are sometimes attached to (or budding from) adults.