If you've ever hiked the Bright Angel Trail down into the Grand Canyon you know there are these narrow passages where an apron of gravel falls away from the trial at a steep angle, then stops right at a 500 foot drop.
This was the inspiration for the sequence in our graphic novel where Mickey Free decides he wants a mule. In our story Free is a scout for General Crook when the U.S., with permission from Mexico City, sent a massive force into Mexico after Geronimo and his band. While traversing one of the perilous switchbacks in the Sierra Madres, one of the mules in front of Mickey got bumped and slipped off the trail into loose shale and slid straight down to one of these ledges. Instinctively, the mule flattened out, which slowed the rate of descent, but the mule was still left dangling over the edge:
This was followed by an avalanche of sand and gravel pouring over the poor pack animal. Everyone up on the trail looked on helplessly and virtually everyone thought the mule was a goner:
Within a few moments all that could be seen was a pile of sand at the lip of the cliff. But then, a lone hoof broke out of the sand and planted itself on a rock. Pulling itself up off the ledge, the mule literally climbed back up on the trail, shook itself off and went on trotting up the trail:
This prompted Mickey to say, "I want one of those!"
"You just go as deep as you possibly can, even where you don't even like the things that you're thinking about or you're feeling."
—Billie Joe Armstrong, Green Day