"Store water now," warned Khidr. "New water is coming that will drive you mad."
Only one man followed Khidr's advice.
The rivers, lakes, and oceans dried up. Then rains fell: rains of new water.
People drank the new water, and they lost their minds.
Meanwhile, the one man kept drinking the old water.
He knew everyone was mad, but they said he was mad. He remembered what had happened; they said he was imagining things.
Finally, he too drank the new water.
He also lost his mind, and he no longer remembered where he had stored the water of old.
Inspired by: Tales of the Dervishes by Idries Shah, free to read online at the Idries Shah Foundation.
Notes: This is on p. 10 in the book. Shah explains that this story is associated with Dhun-Nun al-Misri (the Egyptian). You can read more about Al-Khidr at Wikipedia also.