I remember in High School, I'd already been a huge Lovecraft fan and this guy I knew who was at best a complete jackass, had just heard about the Necronomicon somehow so I convinced him (apparently I rolled damn good on Charisma that day) that it was a real book and I had a copy but it was powerful and evil, and I wouldn't just give it away. The dude begged me for it for weeks, while I prepared a leatherbound blank book with gibberish, drawings and calligraphy (I was really bored and went way out of my way to prank this dude, I did not like him). Eventually I finished it and he paid me about $200 and I gave it to him under cover of darkness, in a parking lot at midnight.
Dude made an ass of himself at school the next day claiming he was invincible after reading from the book for 7 straight hours or some shit and promptly got his ass handed to him by one of the guys from the wrestling team after taking a swing at him.
Lesson, don't piss me off enough to where I convince you that you can become IRL invincible I guess?