To sneak up to someone in the dark and beat them with a clock, light, fan, or broken shower head. You can also drop these objects on your victem while they are asleep. Feel free to squirt water on them and/or turn on their lights to better surprise them if they've really made you mad. Often screaming the word "dairdair" gives a more creeped out effect.
If you don't stop prank-calling me at 3:00 in the morning, I'm gonna freakin' dairdair you, and you won't like it!