Momo may be creepy, but police believe it is clear it is being used by hackers to harvest information.
Officers in Northern Ireland moved to reassure parents about the doll figure with bulging eyes and a creepy grin.
Momo targets young children on social media.
The doll encourages them to add a contact on messaging service WhatsApp, then hounds them with violent images and dares.
It encourages them to self-harm and the ultimate post tells them to take their own lives.
If adults are concerned or have any questions on how to approach the subject with their children, they can contact the NSPCC Helpline on 0808 800 5000 or visit the NSPCC website.
Children who are worried about their activity on apps or online games can contact Childline 24 hours a day, online and over the phone on 0800 1111.