How it's played?
Scream is a GDX twist on the game  "Look Up-Look Down" Make a circle of 6 to 12 players, all standing very close to each other. Each circle will have a player that will be the "caller." This player will start the game by saying , "Look Down!" Each player lowers his or her head and looks down at the floor. When the caller says " Look Up," all the players must raise their heads and look directly at another players in their circle. This is where the GDX variation comes in.  If any two players are looking at each other, they engage in a scream-off to see who is out of the game. The player who screams the longest stays in the circle while the other backs away from the circle, the circle closes up and the commands are given again. Players continue to dropout until there are only one player left.

Write up source: Mike Spiller; Games of the World