Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. Schools are warning parents to keep an eye on what their children are watching on YouTube after an online suicide game reportedly appeared in seemingly innocent videos like Peppa Pig.Teachers used social media to draw attention to the “highly inappropriate” clips showing the creepy character Momo.Originally created by a Japanese special effects company, the character has bulging eyes, a distorted wide mouth and the body of a bird.It encourages youngsters to hand over their mobile number and correspond with Momo, who sets them “challenges” involving self-harm and eventually suicide.Schools have published warnings on social media telling parents about the sinister game and urging them to monitor their children’s internet activity.Momo was reported to have infiltrated the popular video-sharing platform YouTube, appearing in programmes such as children’s cartoon Peppa Pig and clips of the video game Fortnite.The disturbing challenges have been linked to the death of a 12-year-old girl in Argentina. Other worrying stories include a five-year-old girl who hacked off her own hair after being ordered to do so by the sick character. Children who are feeling worried about their activity on apps or online games can contact Childline 24 hours a day, online and over the phone, on 0800 11 11 or by visiting www.childline.org.uk. Haslingden Primary School in Rossendale, near Blackburn, was among the institutions which put out warnings about Momo.The school wrote on its Facebook page: “We have become increasingly aware of highly inappropriate videos circulating online and are being viewed by children across the school. “These video clips are appearing on many social media sites and YouTube (including Kids YouTube).”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.”Another video clip is going by the name of ‘MoMo’ which shows a warped white mask which is promoting children to do dangerous tasks without telling their parents.”Examples we have noticed in school include asking the children to turn the gas on or to find and take tablets.”National Online Safety said they had been contacted by hundreds of concerned schools and parents about Momo.The organisation told The Telegraph that their warning about the suicide game – “What parents need to know about Momo”- had been seen by more than two million people.YouTube said it had not received any evidence of the challenge on its site. A YouTube spokeswoman said: “Contrary to press reports, we have not received any 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.”If adults are concerned or have any questions on how to approach the subject with their children you can contact the NSPCC Helpline on 0808 800 5000 or visit the NSPCC website.