Fan Casting Weasel in Ben 10/Justice League: The Series

John Monroe was a student at Stanford University in the 1960's. He was brilliant but a social outcast owing to his thin frame and narrow features, which earned him the nickname "weasel" by his peers and made him the target of constant bullying. The constant torment drove Monroe to become a sociopath and, decades later, a serial killer. Years later as the adult, Monroe became a teacher at Vandemeer University in Pittsburgh, Pennsylvania until he got himself in the lab accident, turning himself into the Weasel monster. Later he become havoc and killed lots of people he see, including few of his childhood classmates.