Mystery legs and worm.

[Wrench]

I've got some mystery legs that stretch out from under a few of my rocks and I need to ID them so I know if they need to be removed. They're very small, about the diameter of a hair. I've seen 3-5 at once coming from under the same rock which made me think it was a brittle start but they seem to stretch very far. They'll stretch as far as 2" from the rock. They're active during the day but seem more so during the night. They also don't move around much. They've been in the same spots since I put the rock in.

I've also got some worms I'm curious about. I noticed them for the first time while shining a flashlight in the tank during the night. One end of the worm seems anchored to the rock while the other roams around. The body span is up to 1.5". I've found a couple that are white, and also a couple that are brown/white striped. They have no legs or eyes, just a mouth at one end. These guys are 100% nocturnal. They slink back into their holes when they see light.

 

[Fishieness]

the first sounds possibly like a spegettie worm or a micro brittle star
the is a lot harder to identify based on the description but posibly a peanut worm?
here is a pic of the peanut:
http://depts.washington.edu/fhl/zoo432/cattlepoint/432pagemill/PageMill_Resources/image66.gif
the large part will remain anchored in the rock while the thin mouth will come out in search of detritus to eat. They have a crown of little barbs that will come out of their mouth. do you think this is it?

 

[Wrench]

I suppose that could be the peanut worm. I would get a picture of the little stretchy legs but they're waaaay too tiny. The legs are a translucent white with spots that could be stinging cells.