Monkey see, mokey do. 1st poster: X is green. 2nd poster: X is native to Florida. 3rd poster: X is a reptile. 4th poster: X is not a mammal. This breaks a rule: You must actually narrow the options. 5th poster: X's jaws can exert thousands pounds of pressure per square inch when closing. 6th poster: X is the american alligator. The 6th poster wins, and the 5th poster loses. The winner starts a new round. The object of the game is to win or at least to not lose. Someone wins when there are no more subcategories left, i.e., when you reach the category that contains only individuals. I haven't really thought this through, but it's just a game. Oh, and for the children out there (don't make me name names), figments of your imagination or things you saw while under the influence of psychotropic substances, while entertaining, don't count. X is made of latex.