One day you’re floating in your backyard above ground pool. Sipping on a Costco purchased pre-made margarita listening to C&C Music Factory. Life is good.
You head to sleep with dreams of another day of aquatic lounging splashing around in your head.
Wake up the next morning, slap on your trunks only to find an empty husk of pool sadly standing as a monument to disappointment in your backyard. All the water is gone, with no sign of a crack or a seam and all the surrounding grass dry as a whistle.
The solution for many who have had this problem? Aliens.
The phenomenon is explained in depth (no pun intended) on the Inexplicata blog. Interesting stuff.