Is this a budding hammer head?

[Robert Binz]

Or is it something else?

 

[Flippers4pups]

Could be, but most Euphyllia will split at the mouth. This could be a exception.

 

[Tennyson]

At first glance it looks like a tunicate or sponge of some sort.

Babies in that spot are possible, but generally look like a tiny version of the adults.

 

[timrocks311]

I think it looks more like a sponge too.

I have a branching hammer sprouting baby stalks in that area, so it is possible. But they look different than that.