Casper vs Slimer

OK in a battle between the two most friendly ghosts you'll ever meet, who will stand, erm float victorious?
Everything goes, sliming, flying and what not.
Just if you don't know:
Slimer, the (pet?) ghost from Ghostbusters and Casper the Friendly Ghost (come on you know him!).
Everything goes, sliming, flying and what not.
Just if you don't know:
Slimer, the (pet?) ghost from Ghostbusters and Casper the Friendly Ghost (come on you know him!).