Guest Stars Bumper Robinson voices Falcon Laura Bailey voices Black Widow Jack Coleman voices Doctor Strange Isaac C. Singleton, Jr. voices Thanos Trevor Devall voices Rocket Raccoon James Mathis III voices Heimdall Kevin Michael Richardson voices Groot Will Friedle voices Star-Lord Laura Bailey voices Gamora Bumper Robinson voices Armored Army Roger Craig Smith voices Television Announcer Uncredited Phil LaMarr voices Dormammu