Stan Lee, the man who had a hand in creating most of the Marvel Universe, has become known in recent years for his frequent cameo appearances in movies based on Marvel Comics characters. As co-creator of the X-Men, you might expect him to appear in X-Men: Days of Future Past, but he is actually absent from the film. Speaking to CNN, Lee offered two possible explanation. The first is rather innocuous: due to a schedule conflict, he simply wasn't able to take the time to travel to the set of X-Men: Days of Future Past during filming. The other explanation that he, jokingly, offers is a bit more underhanded. "I have a funny theory about it," Lee says. "It also could be they didn't want me to do the cameo because, without my cameo, the movie will make more money…You see, somebody watches the movie and the movie ends and the person says, 'Wow, I didn't see Stan's cameo. I must have missed it.' So what do they do? Right back to the box office, buy another ticket, and watch the movie again. So I think it's a big moneymaking ploy on the part of the producers." Perhaps Lee's missing cameo accounts for X-Men: Days of Future Past's stunning box office sales numbers during its holiday weekend debut. X-Men: Days of Future Past is now playing in theaters.