Black blob ID

[wookiefever]

Hello, I was wondering if someone could ID this blob for me? Not sure if it's beneficial or harmful and needs to be cut off. It feels like a leathery rubber texture.

Thanks,

 

[billdogg]

encrusting sponge. (mostly) beneficial filter feeders

They come in a bunch of colors. I have similar in black, brown, purple, pink, green, red, and yellow

 

[wookiefever]

Okay thanks