|Real name:||Marty Slacker|
|Portrayed by:||Patton Oswalt|
|Appearances:|| The Batman
Marty is a young genius who turned to a life of crime instead of staying in school.
Marty was recruited by the Joker. In his spare time, Marty created a character named "Captain Slash" for an internet videogame and became a constant foe of another named "Nightwing". Captain Slash always managed to get the upper hand. Marty took the game to heart and created the videogame helmet. With it, the Joker could mentally download money rather than the physical effort of breaking into a vault. However, in the theft, the device malfunctioned and created a separate digital copy of the Joker named "Joker 2.0." Marty then realized that Wayne Tech's robot technology could provide it with a physical body. Joker 2.0 went on a rampage. After Robin figured out that Marty was Captain Slash, he uploaded Joker 2.0 into the online videogame and Marty was arrested.