by Mary: Harry Potter book 2, page 72

Several uneventful hours later, Kira decided it was time for a practical joke. Her older sister was the obvious choice for a target, but she had been pranked so many times that she would probably be more careful when she did things like turn the sink on. That had been funny, but after doing it five times already, Kira knew she couldn't take any more chances with it. Her sister definitely wouldn't be expecting the old "jump out a pile of leaves and scare someone" trick, but a giant pile of leaves randomly appearing in the yard in the middle of summer would definitely be suspicious and Kira had done that enough times, anyway. She needed something new. Something that no one had ever thought of before. Something to make the most boring summer ever a little more fun. Something like...