One who disappears mysteriously from a group of friends during a show, using fellow concert goers as their smoke screen.
Tim had been last seen swaying near to his room mates. The concert ninja was later discovered passed on top of his bed with one shoe off.
When one is on hold in an automated system, then seemingly a line opens, starts ringing, only to place you back on hold.
I had been on hold for over twenty minutes, the line rang four times, and then they auto-balked me.