Thunderbolt is a mod that gives arrows fired from primary bows a 7.5% chance per rank (for a maximum chance of 30% at Rank 3) of exploding on impact, dealing 250 Blast damage to any target caught within its 10-meter blast radius (with damage falloff scaled by distance).
- The explosion will deal self-damage to the player if they stand within its blast radius as well as knocking them down if the Blast status effect procs. Self-damage is capable of killing the player if their effective health is low enough, and the knockdown effect can potentially leave them vulnerable to enemies.
- The blast radius is exactly 10 meters and is not affected by mods.
- As of Update 7.11, the 250 Blast damage is not affected by mods.
- As of Update 8.0, the mod was changed from being exclusive to the Paris to working on all bow-type primary weapons (with the exception of Lenz, likely because it already features a delayed explosion of its own.)
- As of Update 9.5, the mod drops more commonly from normal mobs than before due to drop table changes.
- Prior to Update 9.8, when Thunderbolt procced, it would replace the arrow's normal damage. This resulted in lower single-target damage than if Thunderbolt did not proc. However, Update 9.8 stopped Thunderbolt's explosive damage effect from trumping the arrow's normal damage. Now, the arrow's damage is applied first, then the chance to explode is calculated.
- Arrows fired at terrain and other surfaces still explode, but not arrows fired at teammates or other allies.
- When the explosion occurs, the projectile of the arrow causing that is actually "dissolved". Thus any subsequent mechanics relating to the projectile will not happen, such as punching through or the spore coming after the arrow of Mutalist Cernos.
- Pair with a high-rank Multishot mod for maximum effect. Calculating per shot, there will be a 48.9% chance of at least one explosion with both Split Chamber and Thunderbolt at max rank. The chance for two explosions is 8.1%. With Split Chamber, Vigilante Armaments, and Thunderbolt there is a 58.4% chance of at least one explosion, a 15.3% chance of at least two explosions, and a 1.4% chance of three explosions.
- When facing groups of enemies at medium-to-long range, maximize splash damage by aiming for a nearby surface rather than directly at an enemy.
- Since explosive damage is unaffected by the amount of time the shot has been charged, rapid shots can be more effective at quickly taking out large groups of enemies.
- Currently, the mod has no effect on a bows' stealth potential. Killing an unaware enemy with an explosive arrow will not trigger an alarm. However, a missed shot will still be noticed by enemies, whether it be explosive or not.
- This mod pairs well with the Attica or Zhuge due to the high volume of fire of crossbow-type primaries compared to other bows, ensuring a very high chance of bolts exploding within a short period of time. Combined with the higher ammo capacity, using Thunderbolt on these weapons is very effective for dealing with crowds.
- Thunderbolt's damage does not scale with content and cannot be increased in any way, resulting in a very low average DPS (damage per shot) boost of only 75 per target, while even a dual-stat elemental mod will boost a weapon's damage for 60% of base for the same mod capacity cost. Because of this, it is not recommended to use this mod against higher-level enemies (above about level 20).
- If an enemy is hit with an exploding arrow directly, other enemies within the blast radius do not appear to be affected by either the explosion's damage or possible knockdown effect.