|This needs a stretch. (Feel free to remove when satisfied of completion.)|
* Skills and abilities.
* History is missing The Caped Crusader Caper details.
The Joker is a Caucasian male, who has painted his face white and dyed his hair green, to resemble a clown. He wears a purple suit with a red bowtie and gray gloves.
Insert details here.
Skills and abilities
Insert details here.
The New Scooby-Doo Movies
The Joker and Penguin were involved in a counterfeiting operation, and they used the haunted house at the Gotham City Amusement Park as their hideout. When Batman and Robin explored the haunted house in order to search for them, the criminal duo used numerous spooky tricks and mechanisms to attempt to scare them away, which proved fruitless. However, they captured Batman and Robin by luring them into a trap room, which they couldn't escape from because the walls were too smooth for their Bat-lines to hook onto anything. When the heroes failed to return, the gang got worried and decided to investigate the haunted house themselves. When they did, they too were subject to the Joker's and Penguin's tricks and traps. However, despite their best efforts, they failed to scare the gang away. In a final attempt to get rid of them, they disguised themselves as skeletons and tried to chase them off. The disguises backfired; Scooby-Doo mistook them for "delicious-looking bones" and started chasing them. They ended up falling into their own trap, the very same one they used to capture Batman and Robin. After their capture, the two villains revealed that while they did pass the counterfeit money, they did not print it; the actual mastermind behind the operation was someone else whose identity they didn't even know. 
Batman: The Brave and the Bold
Insert details here. (Who's Scared?)
Background in other media
The Joker is widely regarded as Batman's greatest adversary. He was originally conceived as a comic-book character by artists, Bob Kane and Jerry Robinson, and writer, Bill Finger, for DC Comics; first appearing in Batman #1 (April 25, 1940).
Joker's first animated appearance was in the The Adventures of Batman segments of the Filmation-produced, The Batman/Superman Hour, which were later repackaged as Batman with Robin the Boy Wonder. He was voiced by Larry Storch, who would reprise the role for The New Scooby-Doo Movies. He also appeared in Hanna-Barbera's The Super Powers Team: Galactic Guardians, voiced by Frank Welker.
In the special Batman: The Brave and the Bold episode, Bat-Mite Presents: Batman's Strangest Cases!, one segment had Bat-Mite show an encounter with the Dynamic Duo and Mystery Inc., and broke the "fourth wall", by pointing out animation mistakes (as if he knew he was watching a cartoon) and made Scooby and Shaggy fight back. Joker was voiced by Corey Burton.
In 2014, DC Comics published the bi-monthly Scooby-Doo! Team-Up, which featured a "reunion" of Batman and Robin and Mystery Inc. in the first issue. The Joker and Penguin are downplayed in the series, in order to focus on Batman's other villains, although they do have cameos in issue two.