For a movie that's meant to represent the birth of a brand-new cinematic universe (the DCU), James Gunn's slight and slaphappy take on "Superman" doesn't feel much like the start of anything.  In part,

Zack Snyder gives James Gunn some unsolicited advice about his 'Superman' movie as the two cameo on 'Rick and Morty': 'He's the Man of Steel, not the Man of Conversation.'

Joining a long list of celebrity voices to have appeared on Rick and Morty, Snyder popped up to play himself. But the main guest star in “Ricker Than Fiction” is James Gunn —whose Superman hits theaters later this week,