Sponge?

[AlmondBoy]

 

[duberii]

Certainly could be- I've never seen one like that but since there are thousands of different kinds of sponges it's hard to say you've seen them all

 

[king aiptasia]

does it have 2 holes up top, i know some caribbean and gulf of mexico tunicates look like this

 

[AlmondBoy]

Certainly could be- I've never seen one like that but since there are thousands of different kinds of sponges it's hard to say you've seen them all

A week ago.

 

[vetteguy53081]

Appears to be sea squirt a/k/a tunicate
Filter feeders best at lower third of tank