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.