Crazy Jane (legal name: Kay Challis) is a superhero appearing in American comic books published by DC Comics. Created by writer Grant Morrison and artist Richard Case, the character first appeared in Doom Patrol (vol. 2) #19 (February 1989), which was published by the DC imprint Vertigo Comics. She has dissociative identity disorder as a result of childhood trauma, and each one of her 64 alternate personalities, or "alters", has a unique superhuman ability. According to the afterword in the first trade paperback collection of Morrison's run on Doom Patrol, she was based on Truddi Chase's autobiography, When Rabbit Howls, which Morrison had been reading while creating the series.

Jane is portrayed by Diane Guerrero in the TV series Doom Patrol on Max along with Skye Roberts portraying Kay Challis.

Crazy Jane is the current dominant alter, or host, of Kay Challis's system (used to refer to every alter someone has as a collective). Kay Challis, as a result of repeated childhood trauma and abuse, developed dissociative identity disorder.

Beginning at only five years old, Kay Challis was continuously abused by her father. The first time this happens, she is putting a jigsaw puzzle together; this becomes an important symbol in her future. As the abuse continues, Kay withdraws and goes dormant, retreating to her unconscious. Her role as host is then taken over by an alter with the name "Miranda". One Easter Sunday while at church, Miranda is raped, which triggers several flashbacks to her former abuse. This causes Miranda to become dormant and create many more alters. She is committed to a mental institution soon after. During that time, the alien Dominators invade Earth and activate their gene bomb. When the gene bomb goes off, Jane and all of her alters are affected and each gain a different power.

Cliff Steele (Robotman) suffers several losses due to this bomb, which killed many of his Doom Patrol teammates. While staying in the same institution as Jane, Will Magnus asks Cliff to look after her, which leads to Jane joining the Doom Patrol.

Jane makes a pilgrimage back to her childhood home, facing her own traumas and overcoming them. This brings peace to her inner turmoil, causing her and her alters to come to an understanding and live in cooperation.

Crazy Jane's alters are organized in a mental subway grid called "the Underground", their headspace. Each alter has their own "station", which appears to serve as home when they are not in control. In the lower section of the Underground is a well where the alters can go to destroy themselves. This is where Miranda was "killed". This well houses Daddy, an alter who resembles their father, in the deepest, most protected part of the Underground. The alters consist of: