Sponge?

[adapt13]

Noticed this thing about a year back. When I first saw it, I tried taking it off but it wasn’t easily removable. Figured I’d see what happens.
since then, it has grown significantly larger, even growing through the rock.

not sure if it’s friend/foe ?

 

[ISpeakForTheSeas]

Looks like a sponge to me.

Generally, with sponges, as long as they're not smothering anything, they're just harmless filter feeders. A lot of people consider them a sign of a healthy aquarium. Personally, I'd say leave it (but I really like sponges) and enjoy your cool find, but that's just me.

 

[AydenLincoln]

Yes!

 

[WheatToast]

Looks like a sponge to me.

Generally, with sponges, as long as they're not smothering anything, they're just harmless filter feeders. A lot of people consider them a sign of a healthy aquarium. Personally, I'd say leave it (but I really like sponges) and enjoy your cool find, but that's just me.

+1
Might be a Clathrina sponge: