Bubbles Underneath Hammer

[atomichead]

I have a three-headed hammer that has recently sprouted bubbles in the area between its white coral base and the fleshy mantle. The bubbles, at their max size, are about an inch across with a thin clear 'skin' and they inflate/deflate with the mantle. Any ideas what it might be?

 

[waltj11]

Not really sure...A picture would help????

 

[tmulrney]

New head growing? Pic?

 

[jrock413]

My hammer sprouts bubbles when its about to split into a new head. But the same hammer colony developed a bubble in the center of one head and hasn't split in about 8 months now
hammers are funny like that

 

[wendy32693]

My hammer has also been splitting heads and the bubbles appear often