A free app for Android, by GhostTube.
GhostTube is a toolkit for ghost hunting. The app is capable of making a variety of sounds with different properties like pitch, frequency, and volume. These sounds are used as communication for the spirit world and are known as a ghost's call. It is also capable of recording and playing the detected sounds. It is able to do this by using the magnetometer on the phone. There is a possibility that there is an explanation for this, but at this point, the app's operation is not yet proven.
This app is also a sound synthesizer and a toolkit for voice recognition.
