Your soul lashes out with necrotic energy at one who would harm you.

Encounter   ✦     Necrotic
Immediate Reaction      Close burst 20

Trigger: A creature within 20 squares of you hits you with an attack.

Target: The triggering creature

Attack: Your highest ability modifier + 4 vs. Fortitude
Level 21: Your highest ability modifier + 6 vs. Fortitude

Hit: The target takes necrotic damage equal to the damage you took from the attack.

Published in Dragon Magazine 376, page(s) 43.