- "Do you cuties need some counseling? I'm a trained therapist."
- —Harley Quinn to John Diggle and Lyla Michaels[src]
While John Diggle and Lyla Michaels were arguing outside of A.R.G.U.S. holding cells, Harley Quinn offered to help them through their problems, claiming she was a trained therapist. Amanda Waller then hit her door to silence her.
- "Suicide Squad" (unseen)
- "Draw Back Your Bow" (mentioned)
Behind the scenes
- "I want to manage expectations with respect to Harley Quinn. She was always intended to be an Easter egg. I don’t want people to go in with incorrect expectations and walk away from Episode 16 disappointed. But there is an element to the Easter egg that was not spoiled by the promo, that I think people will find a lot of fun."
- —Marc Guggenheim[src]
- Producer Marc Guggenheim admitted that although the character was indeed Harley Quinn, a long-time enemy of Batman, the character was simply an easter egg for fans.
- Harley is voiced by Tara Strong, who uses the same voice she uses for Harley Quinn in the Batman: Arkham games and Injustice: Gods Among Us.
- In the 2011 rebooted comic incarnation of the Suicide Squad, Harley Quinn appears as a member.
- According to Stephen Amell, Harley was planned to appear in the Season 2 finale, "Unthinkable"; but the scene was cut due to time.