Extreme geocaching

A former acquaintance of mine is into the sport of geocaching. I was thinking that it would be a more thrilling pastime if one introduced mild hazards into the mix — nothing deadly or terribly hazardous, but just distateful. Tear gas, not nerve gas, if you like. Along with the cache, what about secreting a very ripe durian? A cluster of wolf spider eggs? A small pail brimming with saliva? A paintball booby-trap? Or an emotionally disturbing snip of video?

The finder could be awarded points for getting to the cache having bypassed the hazard, making it more like a bomb-squad mission of sorts for the finder, and like an evil overlord experience for the person setting up the cache.