The act of sneaking up behind someone in a dance-setting, and copying or "ghosting" their moves. For maximal results, when they turn around, look inconspicuous, or greet them like a former acquaintance.
Heather: Guys, watch me Dance Ghost this sick-looking couple!
Kayln: Bonus points if you don't get caught!
*sets up Dance Ghosting position behind couple, and ghosts a horrible rendition of Soulja Boy*
Kighl: You looked like a fag.
Heather: That's how we do, boiiiiii!