The Prize Ball Guardian are seemingly the enhanced and modified versions of Gumball Guardians and function as not only protectors but also mobile living areas of the Candy Kingdom. The guardian is introduced in the episode "Graybles 1000+" where it takes in Cuber mistaking him for Starchy. Due to its short appearance in the episode, not much is known about the guardian, but it's worth noting that the internal recreation areas featured as Cuber was being transported upwards are all dark and unused, with the candy people all being stored. Beth and Shermy encounter one in "Come Along With Me", and discover Finn's robotic arm in one of its footprints.
The guardian is seemingly an enhanced and futuristic form of the Gumball Guardians. It has a cuboid-shaped head, which contains the citizens of the Candy Kingdom in prize containers, hence the name, Prize Ball Guardian. It is very tall, has a dark pink body color, and also carries a boomerang/gun at their waist.
Prize Ball Guardian is based on a Gashapon machine, a popular vending machine that exchanges quarters for small toys enclosed in plastic capsules.