The National Geographic web site has a very cool gallery of strange Hawaiian worms up from their current print issue. Here’s how they describe this one:

The intricate parchment worm, this one about five inches (13 centimeters) long, is typically well-hidden in a U-shaped tube in the sand—through which it pumps water using paddles at the center of the body. Edible bits are caught and balled up in sticky mucus bags that form below the rectangular head. When disturbed, this remarkable animal can expel bioluminescent mucus.

Via the LiveJournal Invertebrates Community