- Okay, losers! Which one of you is the ghost? Start talkin' or it's hammer time!
- — Harley Quinn src
History of character has not yet been written.
- Unique Physiology: Due to his chemical submergence, Harley gained beyond average advantages over normal humans as well as further exposure tainting his physiology.
- Toxic Immunity: Harley is immunized to various assorted toxins and Ivy's own poisonous touch.
- Cheating Death
- Genius Level Intellect
- Gymnastics: She is a very spectacular gymnast. Her skills rival with those of Catwoman and Batgirl.
- Hand-to-Hand Combat (Advanced)
- Martial Arts
- Psychiatry: Trained as in the field of psychoanalysis.
- 4 Appearances of Harleen Quinzel (Scooby-Doo Team-Up)
- 2 Images featuring Harleen Quinzel (Scooby-Doo Team-Up)
- 1 Quotations by or about Harleen Quinzel (Scooby-Doo Team-Up)
- Character Gallery: Harleen Quinzel (Scooby-Doo Team-Up)