- "She ([Dot]) has a pet that she keeps in a small box. She pulls it out as necessary and says: 'Wanna see our pet?' An impossibly huge monster leaps out of the box, scaring the victim, disappearing back into the box. 'Gets 'em every time.'"
- — Animaniacs Pitch Bible
A running gag in the Yakko, Wakko, and Dot segments of the original Animaniacs was that Dot Warner would get out a box and open it to reveal some kind of monster, which she claims is her pet.
Various Forms of the Monster in the Box
- A Mr. Director-esque Xenomorph. ("Taming Of The Screwy")
- A green Cyclops ("Taming Of The Screwy")
- A devil ("Space-Probed")
- A blue giant ("Roll Over Beethoven")
- A bright green giant ("Plane Pals")
- A dark green giant ("Hot, Bothered and Bedeviled")
- A green giant ("Mobster Mash")
- A furry, lime green giant ("Soda Jerk")