Bio-Terrorist

In the Bio-Terrorist challenge (3 or 4 players), one player secretly plays against the team, spreading the purple disease. It can be combined with Virulent Strain, but not with Mutation. The team wins by curing all 5 diseases, or by curing the 4 regular ones and, then or later, removing every purple cube. The Bio-Terrorist wins if the team loses with at least 1 purple cube on the board.