You fire a snap shot at an attacking enemy in retribution for an attack, then transfer the energy from your attack to create a weakening ward around your ally.

Encounter   ✦     Arcane, Necrotic, Weapon
Immediate Reaction      Ranged weapon

Trigger: An enemy hits and deals damage to one of your allies with an attack

Target: The triggering enemy

Attack: Intelligence vs. AC

Hit: 2[W] + Intelligence modifier necrotic damage, and until the end of your next turn any enemy takes a -2 penalty to attack rolls while adjacent to the ally.

Published in Dragon Magazine 381, page(s) 58.