You strike with the strength of a mountain: brutal and unforgettable.

Encounter   ✦     Primal, Weapon
Standard Action      Melee weapon

Target: One creature

Attack: Strength vs. Fortitude

Hit: 2[W] + Strength modifier damage, and the target takes a -2 penalty to melee attack rolls until the end of your next turn.

  Earthstrength: The penalty to melee attack rolls equals 1 + your Constitution modifier.

Published in Player's Handbook 2, page(s) 158.