Mid-credits scene in Legion - Chapter 8

As the credits roll on the last Chapter of the first season of Legion, they quickly shift to a room full of TV screens showing different scenes from the first-season episodes of Legion.

The camera pans around to a creature that closely resembles the Devil with Yellow Eyes, but with cybernetic wiring coming out of the back of it's head. Wires pull its smile into an even wider, terrifying grin, its yellow eyes mechanically held open. Sitting in a mechanized chair, the motorized spider-like legs helping to move the creature from one large screen to the next.

As it turns to the last screen, it says "Perfect! Perfect! Best First Season Ever!"

And the credits roll again.