Looks like Hair

[MaineSalt]

I have a bunch of small tube looking things on my rocks and they keep having something coming out of them. It looks like a hair is stuck on the end of it but it's not hair. There is one right above the mushroom

 

[Animal-Chin]

Thats a type of snail. It spits out the "hair" your talking about to catch food...

 

[Kimlafeiet]

I think its a vermitid snail. I have some similar looking ones in my tank, but I am still very new at this, so I could be wrong.