Critter identification

[marktheshark87]

So basically it seems to be on my live rocks more towards nighttime, they extend arms out with like little white dots on them, if you try to tweezer it or agitate it, it retracts back into the rock

 

[JGT]

Hard to see but sounds like hydroids.

 

[EeyoreIsMySpiritAnimal]

Ball anemone - related to mushrooms.

 

[ChrisPPolys]

agree with ball anemone.