Joseph "Joey" Beetles is the baby brother of Numbuh 4. He is also the world's greatest dodgeball player ever.
Joey is a main character in Operation: D.O.D.G.E.B.A.L.L.in which the episode's villain, The Dodgeball Wizard, triumphs over Numbuh 4 (whom he mistakes for the world's greatest dodgeball player only knowing that the greatest dodgeball player is "the one called Beetles") in a game of dodgeball.
Only to discover that the greatest dodgeball player in the world is actually Joey, The Wizard engages Joey in a spectacular game of dodgeball throughout the city, which baby Joey ultimately wins. Joey is probably a bit less than 1 year old or as he appears.
His name "Joey" probably comes from the Australian slang word "joey", which means baby kangaroo, making him and Wally named after marsupials.
He is also a main character in Operation: S.A.F.E.T.Y., where he danced when Numbuh 4 told him to go home. His dancing saved the day because it distracted the main Safety Robot.