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.
Bro #1: "Watch me dance ghost this guy. He's got some ghost-worthy moves, and I love 'Total Eclipse of the Heart'!"
Bro #2: "Bonus points if you don't get caught."
When you're dancing totally normal, and you hear a song that gets your mojo movin'...so you bust some sick, over-exaggerated dance moves (example: flailing arms, throwing yourself around the room, etc)
"Holy fuck, did you see Joey on the dance floor last night at that bat mitzvah? He went Full Shatner! I've never seen him cut rug like that. Bitch can bust a move."