If i am seeing the correct picture in my head you are talking about when the body swells into a ball and sucks the tentacles in to where you can barely see them. If it is, then my rbta is doing that as I type. They are another animal, and they do wierd stuff sometimes. It may be digesting food if you just fed it, it could be takin a crap. You really dont know, but I've found out that if you just leave it, it will do its thing and look great again in no time. Hope this helps. Good luck