سَرَاب

Appears 2 times in the Quran. (Root: سرب)
  1. And (as for) those who disbelieve, their deeds are like the mirage in a desert, which the thirsty man deems to be water; until when he comes to it he finds it to be naught, and there he finds Allah, so He pays back to him his reckoning in full; and Allah is quick in reckoning;

  2. And the mountains shall be moved off so that they shall remain a mere semblance.