MARVEL'S AVENGERS ASSEMBLE - "Guardians and Space Knights" - When Galactus attacks Earth, Iron Man is able to lead him to another planet but discovers that it is populated and under the protection of the Guardians of the Galaxy. This episode of "Marvel's Avengers Assemble" premieres Sunday, April 6 (8:00 AM - 8:30 AM, ET/PT) on Marvel Universe on Disney XD. (Photo by Disney XD via Getty Images)