Guest Stars Roberts Gannaway voices Roto Rhys Darby voices Roger Rogers Nathan Fillion voices Johnny Bobby Moynihan voices Chet Corey Burton voices Slappy Kurtwood Smith voices Alistair Clawbottom Danny Pudi voices Evan Christopher Swindle voices McLean Ryan McPartlin voices Bully Monster 1 Ryan McPartlin voices Mr. April Carlos Alazraqui voices Business Monster Corey Burton voices C.R.E.E.P. Worker Danny Trejo voices Terry Max Mittelman voices Scared Monster Max Mittelman voices Convention Monsters Emily Peterson voices Fear Co. Narrator Emily Peterson voices Fancy Monster Kevin Deters voices Janitor Stevie Wermers-Skelton voices Scream Can Mascot Stevie Wermers-Skelton voices Bully Monster 2 Christopher Swindle voices Bathroom Monster Christopher Swindle voices Four-Eyed Monster Cody Rigsby voices Spin-Ergy Instructor Monster