you can scare someone in many different ways. It depends if they are a wimp or not. To see if they are a wimp; jump out from behind a bush. If they jump or scream then they are classed as wimps.
Another way to scare someone is to lie down. Close your eyes and tell them to bend over and stare straight at your face. When you are ready, and it is an awkward moment open your eyes, mouth and scream! It will scare them half to death...
hope this helps.