The Maze houses strange, lethal creatures known as Grievers. Creature designer Ken Barthelmey designed the monsters called Grievers for the film. That night, the Maze entrance does not close while others open, letting Grievers pour in. Creature designer Ken Barthelmey designed the Grievers for the film. Fighting Grievers as they go, Jeff and several other Gladers are killed. Grievers are described as amorphous monsters of metal and flesh.