My wife and I just did. You ride mules single file down this narrow trail down the side of the cliff of the Grand Canyon. One mile down. Wife and I are near the back, maybe 20 people in our group. She’s in front of me and I see her mule stumble a bit. Kind of scary. I hear my wife say THAT’S ONE. OK, whatever. Half way down her mule stumbles again. THAT’S TWO she yelled. I had no clue what’s going on. Few minutes later her mule stumbles again. I watched as she gets off her mule, pulls a Glock out of her backpack and shoots the mule in the head. I sat there in silence in disbelief for a minute or so, then I yelled ARE YOU CRAZY? She said ‘That’s one’.