Rocket Barrage is one of the racial abilities for the new Goblin race and supposedly part of the [Goblin All-In-1-Der Belt] array of tools. When activated it fires a barrage of Rockets that cause fire damage to the targeted enemy. The Ability shares a cooldown with another Goblin Racial, Rocket Jump, which causes the player to be propelled forward by Rockets.
Theoretically it scales with Attack Power, Intellect, level, and firespell power, so at higher levels it could cause significant damage. Pretty good for an instant attack.
Rocket Barrage trigger's the global cooldown, so use it wisely.