One of the Dolittle trailers teases a scene with a dragon guarding some sort of treasure, which appears to set up an exciting climax to the adventure. However, Dolittle isn't a violent person and shows throughout the movie he has nothing but love for animals, so a fight with a dragon isn't on the cards for this finale. Instead, Downey's character realizes that the dragon is in pain, and attempts an operation in order to heal it and end its suffering.
This is all well and good, teaching children watching to help others who need it, even when they may seem scary and angry on the surface. But it's the way in which Dolittle has to help the dragon that has everyone's attention. In order to relieve the internal pressure the dragon is facing, Dr. Dolittle walks around behind it and begins removing things from its ass.
It may sound like a joke, but this is exactly what happens in the movie. Downey reaches his arms into a dragon's anus and just starts pulling stuff out. Skeletons and suits of armor begin to pile up next to the doctor. It's completely bizarre. The final piece to this puzzle is a massive bagpipe that has been lodged in the dragon's rectum. Once Dolittle removes it, the dragon lets out an enormous fart that blows the characters back, and leaves them pinching their noses.
Again, we need to reiterate, not one bit of this is a joke. This is the climactic scene of a big budget adventure movie that is now playing in theaters. For just $13, you can go today and watch Robert Downey Jr. perform an enema on a mythical creature on a 30-50 foot movie screen. Let that sink in for a second.