Now obtain a Zombie Blood, which allows you to see a plane in the sky glowing yellow (similar to the one that dropped a piece for Staff of Fire). When it is shot down, its zombie pilot will drop down to the ground. The zombie will circle the Dig Site in a clockwise pattern, and like the plane it was in, it can only be seen in Zombie Blood. Kill it and retrieve the Maxis Drone it will drop, which now has an upgraded version of its machine gun.