The combination of "creepy" and "crappy" to ultimately form "creppy." Largely used as a method for laughing at oneself and as a way of flirting between creppy lovers that met online.
ANTHONY: Want to watch me through your window as I ride by on my bicycle and take photos of your apartment? KELLY: You're so creppy! Come over and crep on me.
by Doctor Phantom June 30, 2011