Someone who is hopelessly addicted to mung. In actual fact their genetic makeup has been altered to one that requires mung on a weekly basis; every Mungday (monday to non-mungpires).
If you are bitten by a mungpire, after a short period of time the hopeless addiction will begin to take hold and you yourself will become a mungpire.
Some people have taken it upon themselves to hunt down and destroy the mungpires, these people are known as the anti-mungites. So far they have been unsuccesful in eraticating the mungpires.
Closet mungpires choose not to go munging every Mungday but instead, keep a store of mung to drink every mungday, in order to keep themselves alive.
Every Mungpire knows that this stored mung is nothing compared to the rush given by that of mung milked from a fresh corpse.
So beware of mungpires, for if you are not careful, they might claim you as their next victim.
Josh: "Dude, what wrong with you, why are you twitching?"
Evan: "I have this unbelievable urge to squeeze the liquid out of a dead corpses ass and drink it."
Josh: "Thats just fucked up."
Evan: "It's all Mike's fault, he bit me last week and I always knew he was a dirty mungpire. I must have said one too many insults. Now I must live with this for the rest of my life."
Josh: "Wow bro. That blows felch out of Gouthro's and Bronwell's assholes."