This card was inspired by @shannonl5's idea of choosing two female characters that I would love to see team up. I decided to choose two mentally unstable characters from both Marvel and DC.
Harley Quinn (Dr. Harleen Frances Quinzel, M.D.) is a fictional character appearing in American comic books published by DC Comics, commonly as an adversary of the superhero Batman. The character was created by Paul Dini and Bruce Timm, and first appeared on Batman: The Animated Series in September 1992. Harley Quinn later appeared in DC Comics' Batman comic books, with her first comic book appearance in The Batman Adventures #12 (Sept. 1993). She is depicted as having a pronounced New York accent. The character is a frequent accomplice and lover of the Joker, and a close friend of the supervillain Poison Ivy from whom she gained an immunity to poisons and toxins. Harley Quinn's origin story relates that she met the Joker while working as a psychiatrist at Arkham Asylum, where the Joker was a patient. Her name is a play on the name "Harlequin", a character which originated in the commedia dell'arte.
Typhoid Mary (Mary Walker), also known as Typhoid, Walker, Bloody Mary and Mutant Zero, is a fictional character, a supervillain and enemy of Daredevil and Deadpool in the Marvel Comics Universe. Typhoid Mary is an enemy and former lover of Daredevil with low level psionic powers, including telekinesis. She has been a professional criminal employed by organized crime syndicates as an assassin in the past. She is also gravely mentally ill. (Wikipedia)