what are these tentacles

[sample789]

these are coming out the bottom of my hairy toadstool leather. Im not sure if there part of the coral or if its a hitchhiker but its actually pulling the coral frag along the sand bed. there hard to see in the picture but there green with black spots down them almost segmenting them.

 

[dzhuo]

It's kind of hard to see since the picture is a little blurry. On top of that, the picture seems to be rotated incorrectly. If I have to make a guess, this looks like spaghetti worm (since you mention it's pulling the sand) which is harmless.