Cass returned during the 2018 Superstar Shake-up, which moved him to SmackDown. On the April 17, 2018, episode of "SmackDown", he interrupted the main event and attacked Daniel Bryan. The following week on "SmackDown", Cass would take Bryan's spot as the guest on Miz TV, where it would be later revealed that Cass had attacked Bryan backstage. At Greatest Royal Rumble, Cass would enter the 50-man Royal Rumble match at number 49, where he would eliminate Bryan, lasting until the final two before being eliminated by Braun Strowman. At the Backlash pay-per-view, Cass was defeated by Bryan after submitting to the "Yes Lock", only for Cass to attack Bryan after the match. On the May 29 episode of "SmackDown", he would unsuccessfully wrestle against Bryan and Samoa Joe in a triple threat Money in the Bank qualifying match after Joe applied the "Coquina Clutch" on Bryan. At Money in the Bank, Cass lost to Bryan again in a singles match via submission. This would be his last match with the WWE, as he was released on June 19, 2018. According to "Sports Illustrated", Morrissey's release was due to behavioral issues including public intoxication during a WWE tour and disobeying direct orders from Vince McMahon, in particular relating to an on-air incident involving an attack on a little person who was impersonating Daniel Bryan on the May 1 episode of "SmackDown".