The Soul Cleansing Machine is a machine that cleanses evil spirits before they are purified and reincarnated.
In the movie Dragon Ball Z: Fusion Reborn, the Saike Demon guarding the Soul Cleansing Machine is distracted with his psychedelic funk music and his lack of attention allows the machine to become too full. As a result, the machine explodes, releasing all of the evil energy at once. The young ogre is enveloped in the evil smog and is transformed into a giant monster of incredible power named Janemba.
Dragon Ball Heroes
Universe Creation Saga
Dr. W is shown gathering data for the Soul Cleansing Machine in an attempt to grant Janemba more power.