Strange mushroom behaviour

[Reef Pilot]

This morning I noticed a couple of my fuzzy mushrooms puffed up in a ball inside out, with a small opening at the mouth. I have never seen this before. Normally they are just flat against a rock or sand. What are they doing?

By the time I grabbed a camera, the balloon shape was already subsiding, but you can still see the one on the right fairly blown up. 15 minutes later, they were normal.

[Coralgurl]

Mine do that when they catch food.

[Reef Pilot]

Ahh, that could explain it. I did feed some pellets a little earlier. I just hadn't seen that before.

[Coralgurl]

I don't direct feed mine but do notice if they catch something, they almost turn inside out. Freaked me out the first time I saw it too!