Likely developed by climbers or military, a prusik knot allows you to slide up and down a rope, but when you put pressure on it, it locks up. It's a convenient knot to use on your deer stand setup. You loop the prusik knot around your safety line three times, making three clean loops on the rope. The tag end needs to be at least an inch and a half long, with a tight overhand knot. Be sure you test it out before going up.