Joaquin is the most prominent of Sector V's hamsters and their leader. He is also the most often used hamster in Numbuh 2's experiments. In Operation: G.H.O.S.T., he leads the other hamsters against their ghostly counterparts and they attack them using sodas. In Operation: K.I.S.S., Joaquin is used in Numbuh 2's experiment which leads to him accidentally transforming into a teenager and meeting Cree. He later attempted to try to use the ray on himself, only to cause the power in the treehouse to fail, leading to the rest of the events that occurred in that episode. After the power was restored, he apparently succesfully used the ray on himself, growing to an enormous size and transforming into a giant superpowered very muscular hamster. He makes another prominent appearance in Operation: F.O.O.D.F.I.T.E., where he gets Sector V's call for help against Grandma Stuffum and uses the ray in order to fight Slamwich. He defeats the creature by eating it, thus saving Sector V. In Operation: Z.E.R.O., he attacks a citi-zombified Numbuh 5 with other hamsters trying to save Kuki and Wally, but after a brief fight he and other hamsters are zombified by her. They then help her zombify Kuki and find Wally. Later he and other hamsters attack Numbuh 1 and Monty.