Scary Sound Effects is the best app for those who want to add a little bit of fright to their phone. With this application, you can choose from a list of the most popular scary sounds, such as bats, screams, laughter, and more. All you need to do is press each button to preview the sound and, if you like it, press and hold the button to set it as a ringtone, notification, or alarm.

It's also possible to choose from a list of different sounds for each of your contacts, so you will know who is calling without even looking!

This application is easy to use and free.