Philadelphia Flyers mascot Gritty has been accused of physically assaulting a 13-year-old boy at the team’s home arena, according to police.

Chris Greenwell claims the mercurial orange-haired creature “took a running start” and “punched my son as hard as he could” during a meet-and-greet photo shoot for season ticket holders in November at the Wells Fargo Center.

Greenwell said in a Facebook post that his son, Brandon, was diagnosed with a “contusion to lower thoracic spine with subluxation” following a visit to a chiropractor about a week after the alleged flare-up. He claims he initially attempted to get the Flyers to apologize to his son and pay for his medical bills, only turning to the authorities when the team declined.

A Philadelphia police department spokesman described the case as an alleged “physical assault” that occurred “during a photo shoot with 13-year-old white male and Flyers mascot Gritty”, adding the “investigation is active and on-going with South Detectives Division”.

Comcast Spectacor, the company which owns the Flyers, said there is no surveillance footage of the incident because the “cameras in that area of the center are focused on other locations”, according to Greenwell’s account.

Greenwell, who said he has discontinued his season tickets after 22 years, accused the team of bribery in an attempt to cover up the alleged wrongdoing.

“This could have been handled so simply but they tried to bribe me not to speak about it,” he said. “My inbox is already getting media requests. This article is 100% factual of the incident and the Wells Fargo Center refused to let me see the video of it and the police had to get involved in it to get it. They tried to get me to drop it by offering tickets and all I can drink passes at one of the bars there.”

The Flyers said in a statement they “took Mr Greenwell’s allegations seriously and conducted a thorough investigation that found nothing to support this claim”.

Gritty, described in these pages as a “nightmarish frat boy” and “horrifying bearded man-Muppet hybrid”, became an overnight sensation when he was introduced in September 2018, riding appearances on Saturday Night Live, the Tonight Show and Last Week Tonight with John Oliver to become perhaps the best-known mascot in sports.

But Gritty’s meteoric rise to fame came with unintended consequences, including his reappropriation as a symbol for both antifa and alt-right groups.

Philadelphia police confirmed there are no other open or closed investigations involving the mascot, whose official biography on the Flyers’ website admits to “bully” tendencies.

Gritty has yet to comment on the allegations.