Learn a new song and play a fun game
Blindfolds (use neckers). Jelly with hidden bugs, rodents etc, hand-washing facilities and towels.
Pre-make a large bowl of jelly and Angel Delight layers. In each layer, set jelly snakes and bugs, small rubber mice or rats, grapes (eyeballs), plastic spiders and any other bugs you can find. On the evening, teach the Beavers the song of 'There was an old woman who swallowed a fly.'