Numbuh 398 is a guard at the Kids Next Door Moonbase. He wears a pink bucket with a light in it on his head. He works there with Numbuh 116. His first appearance is in Operation: G.R.A.D.U.A.T.E.S..
In Operation: G.R.A.D.U.A.T.E.S., he is seen running twice with other KND operatives.