why is this guy growing out

[CHI-Mark]

Hey All

Can someone explain to me why this guy is growing out like a bubble. Not sure of the name of it is.

 

[SashimiTurtle]

Those are acans. When placed in the sand they will grow out in a nice dome shape. If you put them on rock they will grow out across the rock.

 

[CHI-Mark]

Is this considered a good thing? Don't know to much about acans this is one of my starter corals I got about yearend half ago

 

[CHI-Mark]

Whoa

 

[DSC reef]

Looks similar to a favia with asexual reproduction. Had the same thing happen to our platygyra

 

[Salty1962]

I believe it's a Favia, pushing it's gut out. Maybe to release waste.

 

[mort]

Looks similar to a favia with asexual reproduction. Had the same thing happen to our platygyra

Agree it's a favia and is likely spreading via a less common method. Some corals like stylophora are more commonly seen utilising this method of reproduction where they look like they are melting, with the "drip" finding the substrate and regrowing into a new coral.
You also see inflated areas like with bounce mushrooms. It's more unusual but I've seen it with brain corals, Acans and a few others. So it could be this but it's hard to tell.