When first faced with the threat of dragons in season seven, Cersei tasked Qyburn with creating a weapon that would defeat the beasts. He creates a long-range artillery weapon known as a scorpion to shoot bolts large and fast enough to pierce the skull of a dragon. We learn later in the season during the Battle of the Goldroad that the weapon is not as effective as Qyburn believes.
However, the fact that the weapon and a demonstration of its power has surfaced in the opening sequence leads us to believe that Cersei and Qyburn will find a way to make the weapon powerful enough to finally bring down one of Daenerys dragons.