Its actually the fear of anything involving Thirteens. That's why a lot of buildings go straight from the Twelfth floor to the Fourteenth. If you have this nearly obsolete, number based fear, just take a deep breath and try to avoid any Bar Mitzvahs or Dan Marinos until tomorrow. Until then here's a scary and spooky Bowie song to press your luck.
David Bowie with Frank Black - Scary Monsters and Super Creeps