clear thingie???

[pupeluv]

I would have attached a pic but it was too small and too far back in my tank. Yesterday I noticed a clear thing upright on one of my rocks. It was about 1/4 inch long, kind of like what I imagine a feather duster would look like without its tube. It had a long, thin body (like thread) and tentacle kind of things at the top. Kind of picture a thin little palm tree with the leaves pointing towards the sky. The tentacles didn't move, so I kind of thought it might be an empty exoskeleton from something. Then I saw it twist slowly and move its top horizontally like it was looking around. Later in the day it was still upright but was down on a lower rock. I didn't actually see its locomotion. Can anyone help identify?