John Monroe was a lonely student at Stanford University in the late 1960s. His contemporaries rarely noticed him. If they did, they referred to him in derogatory terms, using words like "Weasel" to describe him. This made him bitter, driving him to become a murderer decades later. The grown Jack Monroe became a teacher at Vandemeer University in Pittsburgh, Pennsylvania. A number of his fellow students from Stanford University held prominent positions. To rationalize killing three of them, he considered them threats to getting tenure at Vandemeer. Taking on the costumed identity of Weasel, displaying great agility, expertise at hand-to-hand combat, and a costume with sharp claws, he stalked the campus grounds and brutally murdered Arnold Lintel, Linda Walters, and a night guard named Chuck Gherkin. When Martin Stein shows up for a job opening as a physics professor, Monroe made two attempts on Martin Stein's life. In the second attempt, he would've killed Martin had he not provoked the transformation of Stein into Firestorm. After a fight, Firestorm unmasked Weasel and sent him to jail. Weasel was later recruited into the Suicide Squad for their ill-fated mission to rescue Hawk. During the mission, he tried to kill the Thinker by cutting Thinker's throat with his claws. Rick Flag Jr. took the Thinker's helmet to regain control over the mission. When he saw the Weasel, the Thinker's helmet told Flag to kill him. Weasel's death was not mourned. During the Blackest Night storyline, Weasel's dead body was seen to be among those entombed in the Hall of Justice. When the BlackPower Rings flew in, Weasel's body was among the dead bodies that were reanimated by the Black Power Rings and inducted into the Black Lantern Corps. In September 2011, The New 52 rebooted DC's continuity. In this new timeline, a slightly revised Jack Monroe Weasel is re-established in the Forever Evil storyline, depicted in a more animalistic state. He was lurking in Central Park when Steve Trevor and Killer Frost were looking for Cheetah. Weasel ambushed Steve Trevor and Killer Frost where he was frozen by a reluctant Killer Frost. Killer Frost told Steve Trevor that Weasel is considered a joke compared to villains Black Bison and Multiplex. Before Steve Trevor and Killer Frost press on, Killer Frost apologizes to Weasel.
Future Weasel
In Batman #666, a special issue set 15 years in the future, a different Weasel is shown as an enemy of Damian Wayne, who has become Batman following the death of Dick Grayson. This future Weasel has canine-like teeth.
