I got a surprise hidden coral ID PLEASE

[Darwin stinton]

When I purchased my first Bubble Tip 3 weeks ago, the little bugger wouldn't let go of the rock it was on. The fish store broke away as much rock he could then sold it to me. After I placed it in my tank the next day it had moved and to my surprise there was something I hadn't seen before. Can anyone tell me what it might be?

 

[reef lover]

The corals a mushroom and looks like a spiny brittle star arm in the background.

 

[Salty1962]

@Lionfish Lair ?

 

[Tahoe61]

The corals a mushroom and looks like a spiny brittle star arm in the background.

That is what I see as well.