second to that would be a device that painlessly and non-destructively "inspired" anemones to release from liverock.
I've successfully used ice cubes in the past (in tank) to get an rbta to let go of a rock. I rubbed the ice on the edge of the foot and it irritated the anemone enough to release slightly from the rock. At which point I was able to gently "peel" it the rest of the way off.