In a competitive drinking game situation, usually beirut, a team predicts a victory, or a "sweet come back," only to lose the game.
Can also be spelled Swedish Cum Back.
"Dude, we're totally going to kick your asses! I don't care if you've hit seven cups and every shot we take misses the table, this come back is going to be insane! We're heating up!" would qualify as a Swedish Come Back if the team choked and lost a few cups later.