A disturbing playground activity has parents pissed after finding out what was going down during recess at an elementary school. 

New Ulm, Minnesota, Washington Elementary School is at the centre of controversy after learning fifth grade students played a game they called ‘rape tag‘ during recess. 

The game is very similar to freeze tag, except to unfreeze someone, fifth grader would have to simulate a sex act on the frozen student.

A parent reported the incident to the school’s staff after seeing their child was talking about the game on Facebook. The school said it took immediate action, talking to teachers who later discussed it with their students.

DailyMail reports The school’s principal, Bill Sprung, told KEYC-TV: ‘This age level of kids – 10, 11, 12—is a time when kids start to mature; start to experiment. He added: ‘Part of that experimentation is that they do things we wish they wouldn’t have done.’

The game is very similar to freeze tag, except to unfreeze someone, a student would have to simulate a sex act on the frozen person  Mr Sprung told the station that he quickly alerted teachers, who spoke to their classes about the game.

While it appeared to stop there, rumors about the game continued to appear on Facebook, prompting Mr Sprung to send a letter to parents. The letter went home with students on January 30- 20 days after the parent first reported the incident.

The letter read: ‘On January 10th, a 5th grade parent informed me that 5th grade students were playing a game called “rape tag”.