Canterbury have launched an investigation into footage circulating online which shows a group of Bulldogs supporters surrounding and pushing Canberra drummer Simon Tayoun.
Tayoun has become a cult hero among NRL fans, carrying a drum to every Raiders home and away game and leading the club's "Viking clap" celebration after wins.
After Canterbury pipped the Raiders in a seesawing 22-18 win at Belmore Sportsground on Sunday, footage showed the popular Canberra fan being surrounded by several Bulldogs supporters.
One squared up to Tayoun before another tackled him to the ground from behind as a group of fellow Canterbury fans watched on.
Canberra have been contacted for comment while Canterbury said in a statement they were "profoundly disheartened by the display of intimidation and inappropriate conduct towards another fan of the game".
"While the vast majority of our patrons upheld the values of sportsmanship, this behaviour falls far short of what we stand for as a club," the Bulldogs said in a statement.
"Such actions are unacceptable, and we are actively investigating the situation, including reviewing available footage.
"We are making every effort to reach out to the individual at the centre of the incident to extend our sincere apologies.
"This behaviour does not represent the values of the Bulldogs."