These so called ''casper's'' is down with everything.
They will most likely seem friendly and calm to everybody, but if a mofo is messing with him, be sure to get Casper out of the room, hall, etc.
Also, these persons are very rare, and will most likely only be found in their hood. controlling whatever they do.
When in doubt of the person is really a Casper or not, kick him or slap him. If he is a Casper, he will most likely make a dickish move, either when you are trying to impress a girl, or just when you'r trying to do something cool.
''Hey guys guess what i did last night'' - (one of the mofo's slapping a Casper)
''I dunno dude, but guess what i did last night'' - sticks his 'two fingers' up close to ur nose and yell out - ''YOUR SISTER''