creature id

It's been growing on one of my rocks and on my crushed coral substrate. It looks like bubble algae although I'm not 100% sure it is. If anyone can ID this it would be appreciated.

Is this a fancy worm or a brittle star? I see something that looks like tube feet, so maybe a star? I do not know where i got it from, i saw no stars in chaeto, this piece of rock(the only live rock i bought) or on the small rock with zoas that was gifted to me. Will it divide into more specimens?

Here are the best pics I was able to get. He’s just going around the side glass which has a lot of film algae on it cause I mostly just clean the front. He doesn’t seem to be eating it tho as I watch him. Not once has he truly stopped moving and again I haven’t seen him actually eat the algae...