"Back in my old 72 gallon I had fs do this. Had little inflated tentacle balls rolling around the tank. If I remember correctly it was a form of warfare as what ever the inflated detached tentacles touched it stung. After a day or so the tentacle deflated and melted."
it does shrink at night. It is dropping "balls" of tenticals but it has never been close to anything to stimulate a war response. water is currently at 79.2 no change in the par of the water. it is currently 34 inches from the light, off centered.