The penny challenge circulating on TikTok can be dangerous, firefighters warn. The challenge “involves using the plug part of a phone charger, partially inserting it into the wall outlet, and then sliding a penny down the wall onto the exposed prongs,” reads a letter from the state fire marshal in Massachusetts to firefighters across the country. “The result is sparks, electrical system damage, and in some cases, fire.” InsideEdition.com’s Leigh Scheps has more.