At the end of the closing credits, right after the Dolby Digital logo, there is a strict warning about the flame fart stunt that was performed in the film. Translated from Norwegian to English, it would read:
WARNING!
The flame fart stunt in this movie is done by professionals. If you were to try anyway, you must remember to squeeze again immediately, and wear at least one layer of clothing. If not, the flame can go inside and burn up your whole ass. PS! Apparently there was a guy in the US who burned up his entire intestinal system and died.