It is incongruity theory in action (I only read theories about humor, I don’t name them).
“And in a rambling call to a TV station, Moammar Gadhafi ranted about his enemies, blamed others for his problems. He said he is feeling fine and he is willing to go back to work. So he’s like the Charlie Sheen of Libya now.” (Letterman, February, 2011.)
“Everyone wondering right now what’s going to happen with Moammar Gadhafi,” who “may be unseated. That’s what people are kind of hoping for. … He gave a very defiant speech today.” He “said people protesting against him are quote, ‘under the influence of hallucination pills.’ … In a related story,” Charlie Sheen has “boarded a plane for Libya.” (O’Brien, February 2011.)
It is incongrous to compare a famous actor to a country’s leader, but it worked. Comparing seemingly unrelated things or people works.