Guest Stars Walton Goggins voices Cecil Stedman Zazie Beetz voices Amber Bennett Gillian Jacobs voices Samantha Eve Wilkins / Atom Eve Jason Mantzoukas voices Rex Sloan / Rex Splode Andrew Rannells voices William Clockwell Chris Diamantopoulos voices Donald Ferguson Grey DeLisle Griffin voices Amanda / Monster Girl Khary Payton voices Black Samson Zachary Quinto voices Robot Melise voices Kate Cha / Dupli-Kate Ross Marquand voices The Immortal Ross Marquand voices Rudolph "Rudy" Conners Grey DeLisle Griffin voices Shrinking Rae Seth Rogen voices Allen the Alien Jay Pharoah voices Zandale Randolph / Bulletproof Ben Schwartz voices Shapesmith Cliff Curtis voices Paul Ben Schwartz voices Rus Livingston Scoot McNairy voices King Lizard Rhea Seehorn voices Andressa Ross Marquand voices Omnipotus Rob Delaney voices Nuolzot/Séance Dog Kevin Michael Richardson voices Monster Peter Cullen voices Thaedus Melise voices Iguana Chris Diamantopoulos voices Jerry Khary Payton voices Martian Jay Pharoah voices Komodo Dragon Jay Pharoah voices Sergeant Kari Wahlgren voices Announcer Kari Wahlgren voices GDA Agent Kari Wahlgren voices Female Thraxan Kevin Michael Richardson voices Male Thraxan Ben Schwartz voices Corey Nyima Funk voices Bridget Co Starring Nyima Funk voices Additional Voices Ami Shukla voices Additional Voices Robert Kesselman voices Additional Voices Dan Navarro voices Additional Voices