Okay so we were all ready to attack, but when the round finally started something weird happened. The first thing we saw was Tracer waving at us. She wasn't even attacking us. She was just waving. Granted our other enemies were attacking, but not her. At some point, one of us decided to tell her to just go on with the battle, and then she started shooting her own teammates, killing them all. Now, this was just a simulation to help us practice for real life Overwatch missions, so her teammates would soon respawn, but she still shot her own teammates. Eventually, one of our team members (Junkrat I think) got sick of Tracer's strange actions and finally killed her right by our spawn. In her dying breaths, Tracer pointed to the sky, where we all saw a bunch of orange paint fall on to the spawn. We turned back to Tracer, but instead of seeing her body, we saw a hole in the ground with tentacles coming out of it. The tentacles pulled us into the hole, where a ravaging beast ate us. This continued for the rest of the game.
After the game was over, everyone confronted Tracer, but she said that she didn't know what was going on as she had no control over herself in the simulation, nobody believed her until Winston went into the computer room and saw that Athena's hard drive, which was producing the simulation, had the word, "Sombra," spray painted onto it in pink. It was then we realized that Sombra had hacked into Athena so that the simulation would get messed up. After Winston fixed Athena, we all agreed that it wouldn't have been a problem had Sombra just disappeared forever.