William Morrissey (born August 16, 1987) is an American professional wrestler signed to WWE, where he performs under the ring name Big Cass, a modification of his previous ring name Colin Cassady.
In June 2011, Morrissey signed with Florida Championship Wrestling (FCW), which was [WWE Development Territories|WWE's developmental territory]] at the time. Morrissey made his first televised FCW appearance in July 2011, portraying the dean of the University of Florida. Morrissey wrestled his first televised match under the ring name of Colin Cassady on the September 4, 2011 episode of FCW TV in a disqualification loss to Richie Steamboat.
WWE rebranded its developmental territory, FCW, into WWE NXT in August 2012. Cassady debuted on NXT television on June 5, 2013 with a loss to Mason Ryan. Cassady then formed a tag team with Enzo Amore, who had also previously lost to Ryan, and they labelled themselves "the realest guys in the room". Enzo and Cass would team together through the remainder of their time on NXT and onto the Main Roster on WWE Raw when they were promoted in April 2016. They were spilt in late 2017 when Cass pursued a singles career on SmackDown after a few months off for injury.
On June 19, WWE announced that Cass had been released from his contract.