1 salty-sweaty runner
1 hydration pack with stuck zipper due to salty sweat
1 candle, red is best
1 snake (optional)
first dance around your hydration pack (optionally naked) while repeating unintelligible words for spur-of-the-moment-made-up voodoo song (whatever that sounds like). then rub the candle back and forth on the zipper, trying to open it (or close it, depending on how you left it since your last salty-sweaty run) after every few rubs. (if you choose to use the snake, use your creativity; i have no idea what to do with it). it will eventually work. when it does, light the candle and thank the running voodoo gods.