Wangiri (literally, "One (ring) and cut") is a phone fraud that originated in Japan. The scam involves a computer dialing a large number of mobile phone numbers at random. The numbers appear as missed calls on the recipients' phones. Believing a legitimate call was cut off, or simply curious, users are enticed to call back. The numbers are either premium rate, or contain advertising messages.
A new derivative of the scam has emerged in Singapore, whereby once the user has called the number back and been charged extortionately, a robotic voice will yell BAM. This derivative is called BAMgiri.