A mind burn is when you say somthing so disturbing the mind of the person you told it to actually starts to burn. After the the mind has been burned the burner must tell the burnnie "MIND BURN!"
Burner: "Your mom naked in a bath tub filled with chicken grease making love to the fat kid from the numa numa video."
Burrnie: "Ahhh! Mommie!"
Burner: "MIND BURN"