Pronounced Creeper Stash. It is a thin, finely haired mustache, sported by all manner of sketchy men. It can be used as physical proof that a man is creepy.
Not all men with mustaches are creeps. However, creepy men stereotypically have mustaches like this.
Winnie: "I knew it from the start. I saw his Creeper 'stache, and I turned tail and ran."
Carla: "It's just such a puny, weak tuft of undesirable hair. Who in their right mind would want one?"