Help with ID I’m at a loss

[dking271]

Today I noticed something that I have never noticed in my tank. Tank has been established and running for 12+ years and has BTAs, Ocellaris Clowns, mixed corals, and a few other fish. There are long tentacles (like dental floss) reaching down the rock and a hole in the top. I’m thinking some kind of filter feeding worm. I haven’t tried to move it or see if it is attached firmly. Doesn’t appear to be moving or at least moving fast. Any help with the ID is appreciated.

 

[tzabor10]

Could be a sponge or tunicate

 

[ISpeakForTheSeas]

That's a harmless sponge - filter-feeder.