The Sentry Buster is a specialized robot. It appears as a large pair of legs with a large naval mine for a torso. It has no head, and everything above the waist of the robot is just a large glowing naval mine. It seeks out things to blow up, most of all sentry guns built by Engineers. It beeps constantly as it runs to its target. When it reaches its target, the beeping will become rapid and the mine will spin around before the entire robot explodes violently. Around 4 meters tall.