From Guild Wars 2 Wiki
Fire a ballista arrow through approaching foes. Does double damage to siege weapons.
— In-game description [?]
- The bolt pierces players or siege weapons in its path.
- The bolt travels towards the target's position at the time of activation. The target can move out of the way of the projectile at this time, but the bolt will still hit anything in its path
- This skill is replaced by other versions for players with ranks in Ballista Mastery.