When you have sex in the dark with a girl that thinks you're a different person but you aren't aware she mistook you until after the deed is done.
"How'd you lose your virginity?"
"Oh, I pulled a Casper The Friendly Ghost, once I realized she mistook me for someone else I got the hell out of there!"
Casper the whore ghost is a nasty bitch who does dirty shit like, fucks with other women's relationships or marriages, tries to hard, buys guy food in hopes she'll get the dick, and even decides to try lesbians only to be shot down.
Can be found playing key board warrior, pulling out of gas stations, and running out of Wal-Mart.
Oh look there goes casper the whoreghost again, chasing after that married lesbian with some zaxbys chicken.
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.
FRIEND A: "Did you just take a stealthie of me?"
FRIEND B (turning phone around): "no I was just using snapchat's new filter, see?"