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 Chris Diamantopoulos voices Donald Ferguson Grey DeLisle Griffin voices Amanda / Monster Girl Zachary Quinto voices Robot Khary Payton voices Black Samson Ross Marquand voices The Immortal Melise voices Kate Cha / Dupli-Kate Ross Marquand voices Rudolph "Rudy" Conners Grey DeLisle Griffin voices Shrinking Rae Nyima Funk voices Additional Voices Dan Navarro voices Additional Voices Robert Kesselman voices Additional Voices Ami Shukla voices Additional Voices Jay Pharoah voices Zandale Randolph / Bulletproof Sterling K. Brown voices Angstrom Levy Grey DeLisle Griffin voices Olga Kevin Michael Richardson voices Monster Chris Diamantopoulos voices Todd Chris Diamantopoulos voices Pete Fred Tatasciore voices The Giant Gary Anthony Williams voices Reporter Melise voices GDA Agent Zachary Quinto voices Robot Life Pod Sterling K. Brown voices Angstrom #646 Kevin Michael Richardson voices Random Maulers Kevin Michael Richardson voices Mauler 2 Kevin Michael Richardson voices Mauler 1