Crack the Skull is an encounter power available to Barbarians at 13th level.[PH2:56]
You slam your weapon into the skull of your foe, leaving it disoriented.
Encounter ✦ primal, weapon
Standard Action
Melee weapon
Target: one creature
Attack: Strength vs Fortitude
Hit: 3[W] + Strength modifier damage and the target is dazed until the end of your next turn.