The outlet challenge involves partially plugging a phone charger into an outlet and then touching a penny to the exposed prongs. Firefighters across the country are issuing warnings about how dangerous it is. 
"Behavior like this needs to stop," said Lt. Bill Smith with Grand Rapids Fire Department.
Firefighters in Boston were called to a high school this week to investigate a scorched outlet after kids had attempted the challenge.
"It's a thrill-seeking behavior and as an arson investigator, if I was to respond to the scene and learn of this activity, a person may be charged and may be charged criminally if they were to cause a fire to a structure," Smith said.

Like many social media challenges, this one is incredibly dangerous.
"The material that's coming out is molten and you're not going to be able to put it out quickly, so you could injure yourself. And you're risking great peril to yourself and others and the structure," Smith said.
The fire could stop immediately, unless there's flammable materials inside the wall.
"The material that's inside the outlet that's beyond your scope of view could be enjoined in the fire process and could burn for hours," Smith said. "Imagine going to sleep or leaving the structure and that fire goes undetected."

So far the Grand Rapids Fire Department hasn't responded to any of these calls.
"We're sending out somewhere between 16 and 22 personnel with a full compliment for response, that's a lot of different rigs out of place and the time that somebody else may need us for an emergency," Smith said.
The bottom line is simple: "Don't be stupid, pay attention to what you're doing, find some other activity to engage yourself in, something positive," Smith said.