Thunderstrike is a rune effect in Hammer of the Ancients, a Fury-spending Barbarian skill.
This rune effect stuns every other enemy within 10 yards to be stunned when the Barbarian kills an an enemy with it. This can be quite a powerful CC skill, but must be used sparingly since it only triggers when the kill is obtained with this skill.
Patch 1.0.4 buffed the base skill and added additional improvements to two of the rune effects. Thunderstrike was not modified, but this rune became more effective with the increase in damage of the base skill.
v1.04 changes: 
- Hammer of the Ancients
- Weapon damage increased from 200% to 325%
Skill Rune Effects
See the Hammer of the Ancients rune effects article for thorough descriptions of all the rune effects in this skill, including screenshots and videos.
|| Hammer of the Ancients
|| Cost: 20 Fury|
Call forth a massive hammer to smash enemies directly in front of you for 535% weapon damage. Hammer of the Ancients has a 1% increased Critical Hit Chance for every 5 Fury that you have.
|| When you kill an enemy with Hammer of the Ancients, other enemies within 10 yards are Stunned for 2 seconds.|
Hammer of the Ancients turns into Lightning damage.
Screenshots and videos will be added post-release.
Prior to the February 2012 skill and rune system overhaul, this effect was granted by the An Alabaster Rune, which created the following effect:
Whenever you kill an enemy with Hammer of the Ancients every other nearby enemy has a 65% chance to be stunned for 3 seconds.