Killing someone not-so softly with one's song. Most commonly associated with office workers insisting on the inevitable Birthday song seranade. The most painful version is when one person takes it upon themselves to sing to an unwilling party, thus inflicting serious and irreversible damage.
"OMG, you guys, Marcia's getting ready to Roberta Flack the birthday boy."
"Nah, bro, I'm not going to karaoke with you. Last time, I was Roberta Flacked within an inch of my life'