I believe phaser updates every sprite added to the game( I tried to set alive=false/autoCull=true/visible=false, none of them prevent updating.) But it seems in many games, enemies only move and shoot when they r in the camera view or reach to a certain distance to the hero. I think this is more effective. Any one know how to disable updating when a sprite is out of camera view, and enable it when it's in camera view. Thanks.