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 Melise voices Kate Cha / Dupli-Kate Ross Marquand voices The Immortal Ross Marquand voices Rudolph "Rudy" Conners Grey DeLisle Griffin voices Shrinking Rae Dan Navarro voices Additional Voices Nyima Funk voices Additional Voices Ami Shukla voices Additional Voices Robert Kesselman 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 Melise voices GDA Agent Fred Tatasciore voices The Giant Chris Diamantopoulos voices Todd Chris Diamantopoulos voices Pete Zachary Quinto voices Robot Life Pod Gary Anthony Williams voices Reporter Kevin Michael Richardson voices Mauler 2 Kevin Michael Richardson voices Random Maulers Kevin Michael Richardson voices Mauler 1 Sterling K. Brown voices Angstrom #646