You create an opening that allows an ally to capitalize on your foe's aggression.

Encounter   ✦     Martial, Weapon
Standard Action      Melee weapon

Target: One creature

Attack: Strength vs. AC

Hit: 2[W] + Strength modifier damage, and you choose one ally within 5 squares of you. Until the end of your next turn, if the target makes a melee attack against you or the ally, the ally can make an opportunity attack against the target.

Addition (1/21/2009)
Next to the Action line, add “Melee weapon” range.

Published in Martial Power, page(s) 107.