I can't tell you how many times I've been asked the question: "What are those weird curly mounds of sand down there?" And of course, I explain that they are the excretions--just clean sand!--of a Yellow acorn worm (Ptychodera flava), but that you will probably never see the actual animal, as they stay buried in sand and are so fragile that digging one up would kill it. Today, for the first time ever, I actually saw a Yellow acorn worm (if only the tail end) leaving behind it's trademark mound. I've never even seen a photograph of this happening, so I'm glad to have been in the right place at the right time!
