Gigantic six-legged robotic tank. The construction is farily similar to the Dragoon [...], but it´s much larger and stronger. The height is cca 25m and the width is cca 45m. Although the Dragoon can be teoretically used for planetary defense, only the Expander is able to successfuly hit targets on the orbit from the surface. As well as Dragoon, Expanders fires large amount of antimatter encapsulated in psionic casing. The shot has devastating effect on any target upon impact. Expander can fire on the orbital targets or even on the ground. In that case the hull with the antimatter launcher rotates. The projectile trajectory can be controlled, so the tank may serve even as mortar. However the effectivity od the Expander when used against ground targets does not exceed the effectivity of the Reaver [...], which is much smaller, cheaper and the strength of it´s Scarab torpedoes [...] is still suficient. Therefor Expanders are rarely used in offensive actions, because they are easy targets. But they are perfect tool of planetary defense. Few of them, strategically placed can defend a planet even against a large fleet, if supported by Observers [...] monitoring the situation in orbit. But if necessary, few Expanders behind the Protoss assault ground forces can annihilate the enemy army entirely. Although Expanders are controlled by advanced artifical intelligence, during the fundamental actions, they may be controled by a Protoss warrior directly.