What is this ?

[notafishexpert1]

Hi everyone , I just got a bubble tip anemone for my tank and noticed this weird thing moving next to it while I am acclimating. Does anybody know what it is ?the arms also move

 

[D'sreef]

Looks like a good ol bristle worm to me. Some people call them pest, I consider them a great cuc member.

 

[BlackGoldReefs]

Looks like a bristle star, that is missing many of its legs. Is the body/center round???