It is well known that Cartoon Network shows frequently have cameos of and in other Cartoon Network shows.
KND Cameos in Other Shows
The Grim Adventures of Billy and Mandy
- In the episode "Sickly Sweet", a scene depicts Grim watching Codename: Kids Next Door. Numbuh Four is heard briefly in the background of an episode where they parody KND.
- In the movie Billy and Mandy's Big Boogey Adventure, Numbuh Three is seen in the movie where she is given the position of the new grim reaper after Grim was stripped of his title and scythe.
- In the episode "Taking Nemo / Once Upon a Toon", Numbuh One cameos as one of the cartoon characters who has forgotten his identity and joins all the former Cartoon Network stars to stop the evil witch Dee Dee.
In this movie, the show is seen playing on Miles's mother's television as Miles and Jack leave for a restaurant.