What is my frog spawn doing?

[Grenade Glass]

Came home from work- saw that my frog spawn had a large clear bubble on one of the heads. never seen or heard of this before. Does anyone know whats going on?

A little background, just moved all my corals from a 29 gal nano into a 90 gal. w 30 gal sump. lighting went from 2x24watt T4 and 2x 32 watt PC to 4x 96watt PC and 1x 250watt MH 14K. tank params are stable, my calcium is a little high at 480. everything else is within normal range.

pics:

sorry for terrible pics, ill try to find a real camera tonight.

 

[Ninjapotamus]

Could be splitting. Mine gets those bubbles when its about to split.

 

[droberts]

+one