The primal power of earth courses through your weapon and slams your foe to the ground, where rocks and roots hold it firm.

Encounter   ✦     Primal, Weapon
Standard Action      Melee weapon

Target: One creature

Attack: Strength vs. AC

Hit: 1[W] + Strength modifier damage, and you knock the target prone. The first time the target stands up before the end of your next turn, it takes 1d10 + your Strength modifier damage.

  Earthstrength: The target can't stand up until the end of your next turn, and the first time it stands up before the end of the encounter, it takes 1d10 + your Strength modifier damage.

Published in Player's Handbook 2, page(s) 157.