Continuity mistake: When the Enchanted Princess eats the beer bottle just before the 'Alvin and The Chipmunks' scene, in one shot there is blood in her mouth, in the next shot it's gone. (00:45:20)
Continuity mistake: At one point, at the beginning of the movie, the caveman gets mammoth poop all over his face, in the next shot it's gone.
Answer: It's a spoof of the Sarah Silverman song called "I'm F**king Matt Damon", plenty of versions to view on YouTube.
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