Harley Quinn is seen at the end of "The Titans Show", along with other villains from the DC Comics universe. She don't talk throughout the series.
- Accept the Next Proposition You Hear (cameo on magazine)
- Booby Trap House (cameo on baby pool)
- Scary Figure Dance (cameo on the candy factory)
- Rad Dudes with Bad Tudes (cameo on sticker)
- The Titans Show (in person debut, cameo)
- BBCYFSHIPBDAY (cameo on magazine)