I don't like this "Elf On The Shelf" crap but this is FUNNY! Trap your elf in an upside-down glass cup or vase. Set up your toy soldiers around him as if he had been captured overnight sneaking back into the house from the North Pole.
Jellyfish are strange, with of their body water they don't have a brain, all jelly fish have a squishy hemisphere for a head and deadly stingers that are directly below the head. The stingers kill fish, some jelly fish can kill or wound a human.