Do you have a laser pointer? Maybe for presentations? Or playing with cats?

Don’t point it at a plane.

Seriously. It’s dangerous and illegal.

“When aimed at an aircraft from the ground, the powerful beam of light from a handheld laser can travel more than a mile and illuminate a cockpit, disorienting and temporarily blinding pilots,” the Transportation Security Administration’s website says. “Those who have been subject to such attacks have described them as the equivalent of a camera flash going off in a pitch black car at night.”

That could be incredibly dangerous, especially when planes and helicopters are taking off or landing. “During critical phases of flight, particularly in hours of darkness when the eye is more sensitive to light sources, a laser strike in the cockpit can create a ‘startle response’ which negatively impacts pilot health and flight safety,” said captain Joe DePete, first vice president of the Air Line Pilots Association.

But people can’t seem to stop doing it.

Just Wednesday night, 12 flights reported that lasers were pointed at them as they flew over New Jersey alone, according to the Federal Aviation Administration. Eleven commercial aircraft and one military aircraft reported being illuminated by a laser, an agency spokesperson said in a statement. Pilots across the country reported 23 other “laser incidents” that night.

That’s more than normal, but part of a trend. The number of aviation-related “laser incidents” reported in the United States has increased more than tenfold in less than 10 years, according to the FAA. In 2006, there were 384 reports of lasers being pointed at aircraft. Last year, there were 3,894.

On the bright side, it doesn’t appear that America’s obsession with lighting up planes with laser pointers has resulted in an aircraft crash. But getting caught pointing a laser at a plane can have some serious consequences: It’s a federal crime that could get you years in prison and a hefty fine. The FAA also can impose civil penalties.

Last year, a California man was sentenced to 14 years in prison for repeatedly directing a laser pointer at a police helicopter, although an appeals court later overturned the sentence.