The ability to visit peoples’ dreams, like in Inception. If you haven’t seen Inception, you might just think it’s a cool gimmick that allows you to see what things people wander off doing in their sleep, but the main character, played by Leonardo DiCaprio, is on the run from the government because he’s using it to gain hidden knowledge and influence people who don’t suspect anything is up, almost infinitely. I myself saw him in my dreams too, though I didn’t say a word.