"It's when you do crimes to cause fear, usually in the name of, like, politics? Or religion, I guess? Like bombing a marathon, or shooting up a, like, school or synagogue or something, or flying a plane into a skyscraper -- that's a really, really tall building, like at least twenty stories or something -- or, um, in this joke... giving a bunch of seven year olds recorders and free rein to play them as bad and as loud as they want." Magnus is definitely flushing. Spelled out like that, the joke isn't as funny as he thought it might be.