A viral challenge on the “Tik Tok” social media app has Florida parents and law enforcement officials concerned about their children’s safety, as well as what could be a fire hazard.

“Basically what they are doing is making a connection with the outlet but dropping in a coin to make a spark,” says Major Brad Smith at the Bradford County Sheriff’s Office.

One of the videos circulating on the app shows the “outlet challenge” taking place. It involves partially inserting the brick portion of a mobile device charger into a wall outlet and then sliding a penny down onto the brick’s exposed metal prongs. The result is a blast of electrical sparks.

“That spark could actually cause a fire, and it could be internal to the wall, so that they don’t even see it happening until it creates some serious issues, the other part is that they could electrocute themselves,” Smith says.

Officials in Massachusetts say students have started fires at schools there as a result of the Outlet Challenge.