Your foe might think it has escaped you, but in its moment of triumph, you chase it down and make it pay.

At-Will   ✦     Martial, Weapon
Opportunity Action      Melee weapon

Trigger: An enemy adjacent to you takes an action that provokes an opportunity attack

Effect: After the triggering enemy completes the action, you shift a number of squares equal to your Dexterity modifier. You must end the shift closer to the target than you were when you began the shift. Then make the following attack.

  Target: The triggering enemy

  Attack: Strength vs. AC

  Hit: 1[W] + Strength modifier damage, and you knock the target prone.
Level 21: 2[W] + Strength modifier damage.

Published in Martial Power 2, page(s) 6.