Many years ago SNL created a commercial for the fictional toy line available for the Tom Hanks' film Philadelphia. It was of course completely inappropriate for the tone of the film, just like this Dark Knight-themed Potato Head.
This, however, is real. While it's cute, and Mr. Potato Head has certainly enjoyed a resurgence in recent years thanks to Toy Story and endless movie tie-ins, Christopher Nolan worked hard to erase the Tim Burton and Joel Schumacher Batman films from our minds with his gritty realistic portrayal of the tortured hero. And that doesn't really translate well to a grinning plastic spud.