abbreviate *Fran is a MUNG*
-HEY dude guess wat?
Acronym for, "Fuck, I'm a muggle!"
Used upon the life-shattering realization that while being a witch/wizard would be totally awesome and convenient in his/her current predicament, the speaker is not, and therefore, unable of being totally awesome.
Phrase can be used as an antonym for "super mega foxy awesome hot."
Person A: "Hurry and apperate over here! We're watching A Very Potter Musical!"
Person B: "FIAM!"