Safe or bad?

[Jake337]

There's this squiggly yellow thing that comes out of my lr. When I tried to pick it off it hides back in the rock. I have some pics but there kind of bad quality. Any guesses? Might be a spider? But theres are a ton of tiny tentacles.

 

[Godfrey]

Might be an arm of a brittle star fish. I have tons of them in my rock they are the size of a quarter and all I see of them is an arm or two. Here's a pic of mine in the center there are three arms

 

[Sniperhank]

Though extremely blurry, its the arm of a mini bristle star.

 

[Jake337]

Sorry for the really bad pic but yeah I think it might be but there are a ton of skinny yellow tentacles coming out of the same hole. They are also very long. I've seen some brittle starts on my rock any they don't look alike.