Weapons of mass destruction

Unconventional WMD. AI developed cloaking devices for their walking tanks, making them invisible to the enemy. This cannot be used in conventional warfare as the dropships cannot use this technology, but the unit can be transported in small cloaked capsules even to an inhabited planet, where they assume strategic positions and destroy all barracks. This is possible because of the element of surprise, but the erebus are quickly dispatched by local security. This led the AI to deploy this unit in a spirit of the other races' WMD.