Aereck's caged monkey is a monkey cage containing the monkey that was on Father Aereck's back during the 2021 Birthday event. To catch the monkey, the cage must be placed near Father Aereck or used on him, at which point a cutscene will play of the monkey being lured into the cage.
The caged monkey cannot be deposited into a bank. If players try to bank it, the chatbox will state "A magical force prevents you from banking this item!" On death, the caged monkey is always deleted from the player's inventory.