F4-MF was the leader of the "Rebel Four," an elite task force of Rebel Alliance members. F4 appeared to be an assassin droid of the same model as IG-88. Unlike most assassin droids, F4 was a noble and brave warrior for justice.
While assaulting a group of stormtroopers in an Imperial base on the planet Vatleria, F4 and the rest of the Rebel Four were caught off guard by Darth Vader, who captured the team and executed them in gruesome ways. F4 was pulled apart by heavy machinery.
F4-MF, like the rest of the Rebel Four, is a parody of a member of the comic book heroes the Fantastic Four. F4 is an acronym for Fantastic 4, while MF is a reference to Mister Fantastic, Reed Richards. F4's status as the team's leader, and his demise by being stretched to death are also references to Mister Fantastic and his abilities to stretch his body.
F4-MF, like the rest of the Rebel Four, is a parody of a member of the comic book heroes the Fantastic Four. F4 is an acronym for Fantastic 4, while MF is a reference to Mister Fantastic, Reed Richards. F4's status as the team's leader, and his demise by being stretched to death are also references to Mister Fantastic and his abilities to stretch his body.