Scorpio-Ballista.A photo of a recreated Roman ballista-type &#x27;Scorpion&#x27; catapult. In essence it&#x27;s much the same, but smaller than a basic &#x27;ballista&#x27;. However, this machine was devised as a piece of field artillery. Unlike the full-sized ballista which was a siege engine firing stone balls, the scorpio supported Roman infantry on the battle field by firing bolts at enemy.