Mirages (CR 3)

Mirages are naturally occurring optical illusions that function similarly to illusion (glamer) spells, particularly hallucinatory terrain and mirage arcana. Unlike magical illusions, mirages cannot be dispelled, though they can be disbelieved upon first sight with a successful DC 20 Will save. Mirages are long-distance phenomena in which hazy images appear on the distant horizon, often in the shapes of rock formations, flat pools of reflective water or oases, and city walls. These mirages pose the greatest threat to travelers suffering from dehydration (whose desperation may persuade their minds to believe in an otherwise obvious mirage) or to those using the desert’s few landmarks as aids to orient themselves. When navigating through the desert, the existence of a mirage imposes a –2 penalty on Survival checks to keep from getting lost. Spells such as true seeing indicate a mirage’s true nature but can’t reveal what the mirage is obscuring because of the distance (generally several miles) at which the phenomena are observed. A character who succeeds at a DC 15 Survival check while observing a mirage can estimate the perceived distance to the image. When the character has traveled the estimated distance toward the mirage, he can attempt a DC 10 Will save to disbelieve the mirage. Otherwise, the mirage either vanishes or seems to be even farther off in the distance (equal chances of either result).