To many teens, it's just a game, but to Chris and Julie Wise, it's the practice that killed their son.The Wises spoke at a forum Thursday night at Pendleton Heights High School to educate parents about the warning signs of what teens call the choking game, 6News' Ericka Flye reported.Zachary Wise was a happy-go-lucky, active 16-year-old who played a game that took his life."I would have never guessed in a million years he would have ever tried something like that," said Julie Wise.Many teens take part in the dangerous activity, and there are numerous examples posted on the Internet.The participant gets a brief high by playing, but the results can also be deadly.Teens take part by either choking each other or using a noose to choke themselves.Julie Wise said she had been laughing with her son while watching TV just moments before his death."Little did I know an hour later, I would go walk in his room and find him, and he would no longer be with me," she said.Though they're still grieving, the Wises aren't silent. They want to urge other parents to be aware by being a nosy parent, checking up on their children even when they are alone in their rooms."We had a very open relationship with our kids. We talked about drugs. We talked about sex. We didn't know to talk about these other things," Chris Wise said. "We always gave our kids their space. We let them go in their bedroom and shut their door, and if we had to do it over again, we'd take the doors off."Zach's parents found out he had been experimenting with the choking game from his friends after his death. They urged parents to ask questions of their children, even if they push back.They wish they had learned about the game and asked questions of their son before it was too late."I would rather have a frustrated son that's alive, than a son that's passed away without me asking," Chris Wise said.Unexplained marks and bruises around the neck, bloodshot eyes, disorientation and the presence of ropes, scarves or belts tied to bedroom furniture or doorknobs are signs of the game.