You conceal your arcane attack, tricking your foe into thinking the attack came from one of your allies.

At-Will   ✦     Arcane, Implement
Standard Action      Ranged 10

Target: One creature

Attack: Charisma vs. Reflex

Hit: 1d8 + Charisma modifier damage, and the target is marked by an ally within 5 squares of you until the end of your next turn.
Level 21: 2d8 + Charisma modifier damage.

Published in Player's Handbook 2, page(s) 68.