Broadly defined as anything that is very disgusting. Originally from the acronym "Mash Until No Good" from the practice of making many changes to a code until it is useless. Made popular from the Saturday Night Live sketch "Wayne's World", it was in the top 5 worst things to get in your halloween bag. It was mentioned again in South Park episode 317, this time more narrowly defined as a substance which comes out of a pregnant woman's vagina when pressure is applied to her stomach. And somehow an urban legend involving corpse fluids has sprung off the term mung, though there is no documentation supporting that this is anything other than a gross-out story.
The fraternity had a story about putting mung in the cookies they fed the freshmen. It was so gross!
In a manner similar to the action sequences in films by director John Woo. Excessive violence using a pistol in each hand while repeatedly firing at a person, especially while falling to the side, falling backwards, or rolling. See also Gun Fu. This usually contributes to an unusually large amount of explosions.