Since 2004, Paul Rudd has participated in a long-running gag every time he has appeared on Conan O'Brien's television programs, ostensibly to promote whatever project he is starring in at the time. But instead of a clip from that real movie or TV show, he instead always shows the same clip from the 1980s children's sci-fi adventure movie (and McDonald's advertisement) "Mac and Me," in which a child's wheelchair breaks, runs out of control, and sends the kid careening over a cliff; the alien "Mac" pops up at the end of the clip to save him. When Rudd appeared on O'Brien's show to promote "Living with Yourself," the appearance followed the same format: Rudd pretended to have brought a clip from the real show and even described which scene from "Living with Yourself" the clip would be from, but when it rolled it was instead, once again, the same clip from "Mac and Me"--with one difference: at the end, instead of one Mac popping up, the clip had been digitally altered so that two Macs appeared (a nod to "Living with Yourself"'s cloning theme).
The plot is extremely similar to the Michael Keaton comedy Multiplicity, written by former National Lampoon writer Chris Miller: About a guy who is cloned (to help him at work and at home) and his clone is a better version of himself (and lands him in trouble at work, and with his wife).