According to The Sun, the game has been linked to the United States, Mexico, Argentina, France and Germany.
The Sun reports that the chilling image being used in the challenge is from Japanese artist Midori Hayashi, but he is not associated with the challenge in any way. It features a woman with bulging eyes and a wide mouth.
According to the Independent, the image became popular and gained its current meaning on the "creepy" subreddit, saying the Momo has its own WhatsApp account.
The Sun reports that the game is being blamed for the death of a 12-year-old girl in Argentina.
The Computer Crime Investigation Unit in Mexico put out a warning about the challenge, advising people to avoid talking to strangers on the app.