Long tentacle anemone

Weird but my long tentacle anemone has disappeared. It has been on the same rock for three weeks now. I go to the store today and an hour later its gone. I can't even find the pink ball it goes into when the tentacles aren't out. I only have a 30 gal tank it has only 4 pcs of decent size live rock as far as fish i have two damsels a coral beauty angel two emerald crabs and a sand sifting star. I can see all around my tank and i don't see it. Dont see it jumping out but yes i have a lid on my tank. Don't see why or how but did something eat it and if so that fast or did something else happen. I would hate to disassemble my tank to find it