From Guild Wars 2 Wiki
Bouncing is a property of some skills which allows them to hit enemies after their initial target. Unlike piercing attacks, bounce is not limited to targets in a straight line.
- Bounces are consumed for each target after the initial target. For example, a skill with 1 bounce can hit up to 2 targets. 2 bounces hit up to 3 targets, etc.
- Skills can bounce to the same foes/allies multiple times (ie a skill with more than 1 bounce can bounce between 2 targets multiple times, such as foe 1 to player 1 to foe 1 to player 1, etc.).
- Skills that can bounce between foes & allies may bounce between foes or allies consecutively and may bounce only between foes or allies
- The target of the bounce is typically the closest valid target
- The range of the bounce may be shorter than the range of the initial skill
- Skills can bounce even after the target is defeated if the skill was cast when the target was valid.
- The speed of the bounce projectile appears to be based on the speed of the initial skill (fast attacks = fast bounces, slow attacks = slow bounces). It is thus easier to evade slow bouncing attacks.
- Some skills may not bounce to the same foe if it was already hit by the skill (e.g. Magic Bullet).
- If there are not enough valid targets, then the additional bounces are wasted.
- Bounces may be reflected