In high school some joker convinced me to read one of Castenada's books. Pretty sure it was called A Separate Reality.
Here's the gist: Dude goes to Mexico or somewhere in Central America, hooks up with an old native guy who calls himself don Juan and fancies himself a shaman or something. Throughout the book dudes are munching on peyote buttons (mescaline) like they're jelly beans and seeing funky shit go down. (Surprise!) Apparently, the fact that everybody sees weird shit when they trip is proof that there's an alternate universe that they can tap into and the don Juan dude is the master of said world. Don't confuse this with Fear and Loathing where Hunter Thompson eats an assload of drugs and realizes its fucking with him.
At one point the author thinks he's running with a pack of wolves or chupacabra or something. He's pretty sure there's a warm, golden light everywhere. When he comes down he realizes a bunch of local mutts have pissed on him. (Not kidding.)
There's other shit. Don Juan climbs a tree and floats around in the air because he's standing on a branch that can only be seen in the alternate universe or some nonsense. Bunch of other groundbreaking stuff that I can't remember. The dude's proof that all this stuff went down?
He says it did.
Its real deep stuff. Really makes you question reality.