Sheffield Steelers' mascot was ejected from the arena as passions boiled over during their ice hockey cup final defeat by Cardiff Devils.
Police in Wales are investigating following complaints by the man inside the Steeler Dan costume and a Sheffield fan who was also thrown out, about their treatment by security guards at Sunday's EIHL Challenge Cup Final.
Spectator John Harper accused staff at the stadium of using 'excessive force', ripping his shirt and bruising his arm in the process.
The Devils defended the guards, saying they acted appropriately and had no choice but to kick Steeler Dan out as he was 'yelling' at fans and 'trying to interfere with' the goal judges.
Garry Dickinson, a lawyer representing the Steelers, said Steeler Dan - whose true identity remains a closely guarded secret - had been spat at, punched and kicked by fans, though the Devils deny he was physically abused by anyone at the arena.
Mr Dickinson said the mascot had asked for protection but was instead 'manhandled' out of the arena and not allowed back in until the match was over.
"I have been watching ice hockey for more than 25 years and there have always been friendly rivalries but I've never known an edge to games like the one which has developed between the Steelers and the Devils," added Mr Dickinson, who said both the mascot and the fan had filed complaints with police.
Steelers fan John Harper said he had objected to Steeler Dan's treatment by the guards, only to be told to leave the stands himself.
When he refused to budge, he says he was roughly handled as he was forcibly removed and 'thrown' into the fire door.
Although he was not seriously injured, he says the way he was treated in front of 1,500 travelling fans left him 'embarrassed and humiliated'.
"I just wanted to make a peaceful protest about the way they were treating the mascot. I didn't expect them to use excessive force the way they did to remove me," he said.
Todd Kelman, managing director of the Cardiff Devils, said: "The Sheffield mascot was trying to interfere with the goal judges, who complained to the stewards. He was also verbally abusive to our stewards and yelling at fans.
"He was asked to calm down numerous times but he did not do so. We asked both fans to stay in their own zones, so as not to antagonise fans. He chose not to do that.
"If our security staff felt he was stepping over the mark they were entitled to remove him."
Mr Kelman added that staff had acted appropriately in removing the mascot and Mr Harper from the arena. He said this was only the second time this season that staff at the arena had ejected anyone during a game, having previously removed a drunk spectator.
South Wales Police confirmed it was investigating a complaint from a spectator following an attempt by security staff to eject him from the arena on Sunday.