A number of school across the country have posted alerts on their social media pages, telling parents of the “highly inappropriate” videos.
According to the Parentzone website, the Momo Challenge is played over WhatsApp, with the Momo character asking would-be participants to contact “her” and carry out a series of challenges – the final one being suicide.
The Momo character features a disfigured face with stretched features attached to a bird’s body.
But Haslingden Primary School in Rossendale, near Blackburn, has posted a warning to parents on its Facebook page.
The school said: “One of the videos starts innocently, like the start of a Peppa Pig episode for example, but quickly turn into an altered version with violence and offensive language.”
But YouTube said it had not received any evidence of the challenge on its site.
In a statement to the DailyDot the firm said: “Contrary to press reports, we’ve not received any recent evidence of videos showing or promoting the Momo challenge on YouTube.
“Content of this kind would be in violation of our policies and removed immediately.”
The Samaritans charity was also sceptical.
Speaking to the Guardian a spokesperson for the charity said: “These stories being highly publicised and starting a panic means vulnerable people get to know about it and that creates a risk.”
“Currently we’re not aware of any verified evidence in this country or beyond linking Momo to suicide.”
“What’s more important is parents and people who work with children concentrate on broad online safety guidelines.”