D.B. Cooper is the name given to an unidentified man who famously hijacked a Boeing 727 airplane, extorted hundreds of thousands of dollars in exchange for the release of passengers, and then parachuted out of the plane. Cooper and the money were never found.
As Conan points out, one major aspect of the theory is that Hamm apparently looks a lot like a police sketch drawn of Cooper after the hijacking.
"I think all police sketches, without mustaches, of white guys, look like Jon Hamm," Weiner said, laughing. "He has very cartoon-favorable features."
Weiner refused to shoot down any theory definitively saying, "I'm not going to dismiss [them], because I want people to watch the show."
However, one big factor limiting how crazy the finale will really be is the budget.
"People think it's going to end in a plane crash, which Lionsgate would never pay for," Weiner said.
"So just because of the budget, people can probably figure out what's not going to happen," Conan added. "Because of the budget, it won't be a comet hitting the earth, because that costs a lot of money."
To finally put all the rumors to rest, Weiner actually brought a clip of the shocking closing moments of the series finale, which showed in stark, brutal detail what fate really befalls Don Draper.
He kills himself by jumping out a window. Also, he's recast with a watermelon.