This close to the kill, your instincts take over.

Encounter   ✦     Beast Form, Implement, Primal
Standard Action      Melee 1

Target: One enemy

Attack: Wisdom vs. Reflex

Hit: 1d12 + Wisdom modifier damage. If the target is bloodied or reduced to 0 hit points by this attack, you gain temporary hit points equal to one-half your level.

  Primal Guardian: Add your Constitution modifier to the temporary hit points.

Published in Primal Power, page(s) 38.