D&D4 Wiki
Greater Echoing Weapon
Bard Attack 17

Your touch causes vibrations to shoot from one end of the weapon to the other, filling the air with a low rumble.

Melee 1

Target: One weapon

Effect: Until the end of your next turn, the next weapon attack made with the target weapon deals 3d6 thunder damage to one target of the attack, whether the attack hits or misses.

Greater Echoing Weapon is an encounter power available to bards at the 17th level.[HotF:65]