Virus Wars is a two-player ancient board game that simulates an evolution of two colonies of viruses, which are growing and absorbing (zombifying) each other. The exact origin of the game is unknown but it was actively played as a paper-and-pencil game in Saint Petersburg State University in 80s. There were several variants of the game with slightly different rules. Players must make five steps per turn. Each step is either placing a new virus on the board or "zombifying" one of the enemy viruses. The goal of the game is to leave the opponent without legal moves.