The act of involving yourself in; or creating a terrible situation for yourself and those around you resulting in the complete and total destruction of the mood and/or general vibe.
Similar to a buzz kill, a gafargle may often times result in a cock block, a bad mood, an early ending to a party, less friends and more haters.
Made popular by the band Trap House Rave at a party during a game of Quelf, a popular board game similar to the drinking game KINGS. The word was coined only moments before actually coming into play in a real life situation (See Example). Since then the word has taken on a life of it's own and has even been used by several celebrities and musicians.
When that girl made up all of those lies about that guy to his girlfriend, she caused quite a gafargle for everyone at the party, therein ruining the evening for everyone.