There's an invisible killer prowling the entirety of the desert on a schedule both predictable and unposted. It swallows everyone and everything at once, and begins squeezing until we're either dead or it's time for departure has come. It will come again tomorrow, a little sooner or later depending on the season. It disappears for some months while its less dangerous fraternal twin takes its station. There's a short season of overlap when both twins can be met on the same day; though never at the same hour. Remember that these killers cannot be seen. Are soundless. Have no mind. And are utterly without mercy.