weird anemone

I got this anemone almost a week ago and it's been in my quarantine. I'm pretty sure it ate about 4 days ago. Sometimes it will completely deflate in the middle of the day and now it's doing this! What do I do? What's happening?

I found this weird anemone with a brown foot/stem and purplish blue tipped tentacles. It was on some Indonesia ocean cultures live rock. The rock has been there for about four days and when I looked at the anemone earlier it was small, just now it became bigger. A smaller one