anemone reborn... or never died...

So the last time I saw my anemone with it's tentacles was right before he managed to trapped himself in the filter on my tank. I managed to catch that and then move him to another part of the tank where it appeared he was doing ok for a few days. Then one day I go in and it's just laying on sand and it looked like it's tentacles were eaten or fell off or something and it wouldn't move. SO I assumed it was dead. Rather than pull it out and throw it away I left it in the tank. Just last night I was moving the rocks around in my tank and noticed he was stuck to the rock. like he crawled up and suctioned onto it trying to catch food. I guess he's still alive and doing ok, do their tentacles grow back or do you think they're just not extended all the way?

 

Yes they will regrow tentacles! My Long Tentacle Anemone got sucked up in one of the powerheads three times. Fortunately I caught it soon enough, and was able to shut the powerhead off. Then I waited for the anemone to free itself, instead of trying to pull it out which would definitely resulted in the demise of the anemone.
Sure enough, it regrew all of its tentacles and has returned to the way it was when I bought it. No scars or anything-looks as if nothing ever happened.