Chelsea Cunningham was the best friend of Dana Tan.
Chelsea was an average student and one of the most popular girls from a rich family, though she did not get along well with her father. She was a cheerleader, and has had several boyfriends during her school years: Mason, Rick, and Nelson.
Chelsea's attitude towards everything has landed her into trouble on several occasions. Her father first sent her to Ira Billings for counseling, but it ended up getting worse. Billings forced her to take a precious statuette from her father's art collection, and drop it in the river. The case made the news, and Mr. Cunningham used his connections to get the police to investigate it. After a chat with Billings, however, Commissioner Gordon closed the case, assuming she just made up the encounter though quickly opened it back up after a crime related to the case of Chelsea.
Later, her father sent Chelsea to a rehabilitation clinic run by Dr. David Wheeler after an email to Principal Nakamura protesting the facility and its impact on school attendance resulted in a call to him. The clinic turned out to be a facility that was more akin to a prison, which used brainwashing tactics reminiscent of cults as a means of breaking the spirits of the students and sensory deprivation or "ISO" as punishment. She was rescued when Terry McGinnis infiltrated the facility, got evidence from her about the goings-on at the clinic and helped free everyone as Batman.
Chelsea was very popular with boys, even those who were way below her league. When Howard Groote got a beautiful girlfriend, however, she was interested, much to Cynthia's chagrin. She tried to push the sign of Hamilton High on top of Chelsea, but Terry delayed her. After Cynthia was revealed to be a robot, Chelsea lost interest in Howard.
After Dana was hospitalized from an assassination attempt on Terry McGinnis by the Jokerz, Chelsea agreed with Terry to keep tabs on Dana's status while he left for Wayne Manor to get answers regarding the Joker.
- "Rebirth, Part I"
- "Black Out" (Cameo)
- "The Winning Edge"
- "Terry's Friend Dates a Robot"
- "The Last Resort"
- "The Eggbaby" (Cameo)
- "Inqueling" (Cameo)
- Goodman, Robert (writer) & Lukic, Butch (director) (May 1, 1999). "Spellbound". Batman Beyond. Season 1. Episode 10 (airdate). Episode 9 (production). Kids WB!.
- Berkowitz, Stan (writer) & Geda, Curt (director) (March 4, 2000). "The Last Resort". Batman Beyond. Season 2. Episode 16 (airdate). Episode 29 (production). Kids WB!.
- Fogel, Rich (writer) & Suzuki, Yukio (director) (April 11, 1999). "The Winning Edge". Batman Beyond. Season 1. Episode 9 (airdate). Episode 5 (production). Kids WB!.
- Fogel, Rich (writer) & Lukic, Butch (director) (April 15, 2000). "Plague". Batman Beyond. Season 2. Episode 21 (airdate). Episode 33 (production). Kids WB!.
- McCann, John P. (writer) & Riba, Dan (director) (January 15, 2000). "Terry's Friend Dates a Robot". Batman Beyond. Season 2. Episode 13 (airdate). Episode 26 (production). Kids WB!.