Middletown police are warning parents to be on the look out for suspicious Internet activity, in the form of something known as the "Momo Challenge." The challenge is reported to have shown up in children's apps, on Facebook and YouTube videos, police said. While they don't believe anyone has actually harmed themselves here in CT, rumors are circulating that the challenge is linked to at least three recent cases of minors who killed themselves in Argentina, Colombia and India. It requires players to complete escalating tasks that are usually dangerous and involve self-harm. But, given the challenge's mysterious origins and the unreliability of news reports linking it to actual harm, some question whether it's simply another one of the many hoaxes that breed on the Internet.