Bristle worms Question

Last night I got up and while everything was dark I was looking into my tank with a flash light. Well during this process I happened to notice a bristle worm out near one of my new sps corals. Then while watching I noticed the worm bite the coral. I know that it bit it because every pollop on the coral pulled back in each time he bit it. So the bristle worm bit the coral about 3-4 times and then retracted back into his hole.

After a few minutes the coral was out again as happy as ever. My question is, is this normal? There was nothing special about the bristle worm, just a small long centepedish worm but had barely any bristles.

One other question, does everybody else's hermit crabs play king of the hill at night? Every night my crabs climb to the highest point in my tank (wheather it be rock or a plate coral) and just sit on top of each other.    I just wish they would say off the coral.

Just wondering,
thanks.

Most of the bristleworms in the captive system are very beneficial as to being great detritus eaters and scavengers... IMO, you're safe, but can't be too careful. Watch him and the corals he frequents... should you notice any damage, then you know you are one of very few that has a "bad" bristle worm... As far as "spitting"... hmmmm... dunno??? If I were to take a stab... would be that there is some kind of spawning activities.