When a person comments on someone else's profile, and then rapidly deletes it. Leaving the other person to wonder what was said and why it was deleted. Soon causing them to spiral into insanity.
Sometimes used to simply infuriate the other person, resulting in an "Anti-Comment War", in which both people proceed to comment on multiple things on the other's profile, only to rapidly delete them. Leaving the other person feeling dissatisfied and irritated.
John Smith commented on your status
*Person investigates this new comment, filled with curiosity*
"Oh he did NOT just leave me an Anti-Comment!!"