Rolling Boulder is an encounter power available to Barbarians at 13th level.[PrP:17]
Rolling Boulder
Barbarian Attack 13
You barrel through your enemies, knocking then aside as you bear down on your chosen foe.
Melee weapon
Requirement: You must be wielding two melee weapons.
Primary Target: one creature
Effect: You knock the primary target prone. You can shift 3 squares and can shift through prone enemies' squares. You then make a secondary attack
Whirling Slayer: The number of squares you shift equals 1+ your Dexterity modifier
Secondary Target one enemy other than the primary target
Secondary Attack: Strength vs AC (main weapon) Hit 2[W] (main weapon) + 1[W] (off-hand weapon) + Strength modifier damage.