A warning to parents to investigate what their kids are playing : a video game featuring a shaven-headed teenager who adjusts to life at a new school by harassing others goes on sale today amid criticism from teachers' groups worldwide, including in Canada. "Bully: Scholarship Edition'', an updated version of the original game, "Bully'', is rated Teen for 13-year-old players and is being released for the Nintendo Wii and Xbox 360. The abuse includes dunking pupils' heads in toilets, photographing them naked and physically assaulting them. Both titles were developed by Vancouver-based Rockstar Games. Rockstar spokesman Rodney Walker says Bully is one of the most critically acclaimed games on the market and is a "story that resonates with a lot of people.'' But teachers groups, including the Canadian Teachers' Federation, say the game glorifies bullying and violence. The C-T-F, which is spearheading the call for a ban on sales, says there is a link between violent video games and aggressive behaviour in children. A coalition of teachers groups from Canada, the U-S, Britain, South Korea, Australia and the Caribbean is urging retailers to refuse to sell the game.