Numbuh 78 is the leader of Sector X who first appeared in Operation: U.N.C.O.O.L.. She was also in Operation: Z.E.R.O., shown at the beginning fighting Candy Pirates and in the middle as a Senior Citi-zombie. She appears briefly in several other episodes such as Operation: C.A.N.Y.O.N., Operation: H.O.L.I.D.A.Y., Operation: I.T., and Operation: T.R.E.A.T.Y.. She was voiced by Tara Strong.