"Nerf wars" outside of school hours are now spilling into the classroom in the south Twin Cities suburbs.
A letter sent to parents of Prior Lake High School students is calling on them to help put an end to the potentially dangerous game.
Nerf wars are typically held outside of school hours, and see teams of players using Nerf guns to shoot foam pellets at each other. Some of the games can be quite sophisticated and elaborate, with a long list of rules and a cash prize for the winners.
But the letter says the game has gotten out of hand in Prior Lake and Savage, and has resulted in reckless driving in quiet city neighborhoods.
It's also led to fights in the Prior Lake High School parking lots, threats on social media, students skipping school and "constant texting" during school, including threats to other students.
"This is a serious subject matter and we are asking you to help us by talking to your student and putting a stop to this game that has resulted in violations of school policies and criminal activity in our communities," it reads.
The letter is signed by Prior Lake HS principal John Bezek, and the chiefs of Savage and Prior Lake police.
The game has been the subject of controversy in the past. In 2015, two Lakeville students were killed in a crash while playing Nerf wars.
Police in Grand Rapids last year said students playing Nerf wars were causing complaints of stalking and dangerous driving.