The Full Moon Squeaky Toy is a pet-summoning item which summons a Baby Werewolf pet that follows the player around. It can be purchased from the Zoologist during a Blood Moon in Hardmode, for 30. If the player goes too far away, the Baby Werewolf flies after the player by moving its arms mimicking a bird-like creature.
The Baby Werewolf pet may be an homage to the now-removed Werewolf pet from the Console editions of Terraria.
The Baby Werewolf appears to have a tail, unlike the Werewolf monster it's based on.