Numbuh 5 (a.k.a. Abigail Lincoln) is a character from Codename: Kids Next Door.
Billy & Mandy Moon the Moon
The Grim Adventures of the Kids Next Door
Numbuh 5 appears in Billy's house along with the rest of her team, the Sector V, to try to take Billy's pants from his father, Harold, with the scythe embedded in them. Seeing that did not work, decide with her friends bring Billy to KND Deep Sea Lab to try again.
During the trip with Billy, get a call from Numbuh 362 informing strange activity being conducted by The Delightful Children From Down the Lane, forcing the Sector V to deviate from the path. Arriving at the destination, and after the Delightful Reaper is created, this account his evil plan to assimilate everyone. Except for Numbuh 2, the rest of Sector V flees to the KND Moon Base, which inform Numbuh 362 about the Delightful Reaper while see Mandy posing as Numbuh 1, luring nearly everyone. But only Numbuh 5 knew that she's an impostor, but since nobody else does, Mandy convinces everyone that Numbuh 5 is losing her mind.
Soon Mandy becomes ruler of the KND, renaming it the MND (Mandy New Dictator) and told Numbuh 5 that Numbuh 362 lost her mind, later she rescued Numbuh 1 and Grim in the prison to battle the Delightful Reaper. Thereafter, Numbuh 5 maintains Mandy retained in KND Moon Base with Numbuh 3. After Mandy escape, Billy poses as Numbuh 1, so that everyone starts throwing things be responsible for everything that happened.