Demigods vs Mist

	I was used to the occasional weird experience, but usually they were over quickly. This twentyfour/seven hallucination was more than I could handle. For the rest of the school year, the entire campus seemed to be playing some kind of trick on me. The students acted as if they were completely and totally convinced that Mrs. Kerr-a perky blond woman whom I'd never seen in my life until she got on our bus at the end of the field trip-had been our pre-algebra teacher since Christmas.
...
	"The less you knew, the fewer monsters you'd attract," Grover said, like that should be perfectly obvious. "We put Mist over the humans' eyes. We hoped you'd think the Kindly One was a hallucination. But it was no good. You started to realize who you are."

-The Lightning Thief