It doesn't matter that much what they look like... you put your finger next to one of the arms sticking out from under the rock. They wrap around your finger and you can feel all the tiny little cillia pulling at you... really neat, kind of like a mini finger massage...
Edit: Oops I just realized Red's comment was about all those wierd fish, not the brittle stars
My first thought was that it was a cross between a platypus, a shark, and a labrador retriever...sorry lab lovers, I'm just referring to the tail.
Lisa :happyfish