I've spotted some long (ranging from 2"-3") tenticle type object coming out of a piece of live rock. They look like single strands of white hair. What i'm seeing is a longer piece strung out between two rocks which appears to be pulling in stuff (food?) along side it are two other pieces that are shorter and seem to be feeling around. Does anyone know what it may be (i know it's not bristle worm)? Should i be concerned?