A viral challenge circulating on the social media app TikTok has Massachusetts firefighters issuing an alert.
It's called the "outlet challenge," and it involves partially inserting the plug of a cellphone charger into an outlet, then sliding a penny down the wall onto the exposed prongs.
The result includes sparks and damage to the electrical system. In some cases, it could cause fires, injuries or even electrocution.
At Plymouth North High School on Tuesday, two students were caught performing the prank.
Their teacher told investigators they'd done it twice in a matter of minutes.
Two electrical outlets ended up being scorched.
The state fire marshal's office says there has been an incident in Holden that led to damage to an outlet. At Westford Academy, the challenge also led to a fire.
"Social media elevates it," said Plymouth Fire Chief Ed Bradley. "They see it online, they see someone do it, they start laughing, they run away and no one gets hurt and they assume the same will happen when they do it, so they think it's funny to do it in a classroom."
The students involved in the incidents at schools could face criminal charges.
Firefighters are urging parents to speak with their children about how dangerous these types of challenges can be.