Barbarian Attack 23Crater Fall
You swing your weapon in a great underhand arc and then drive it up into your opponent, sending the foe flying back through the air.
Encounter Primal, Weapon
Standard Action Melee weapon
Target: One creature
Attack: Strength vs. AC
Hit: 3[W] + Strength modifier damage, and you push the target 3 squares and knock it prone. This forced movement ignores hindering terrain, such as a pit, between the target’s starting square and its destination. If you push the target through squares occupied by other enemies, those enemies are knocked prone.
Special: When charging, you can use this power in place of a melee basic attack. If you charge, the number of squares you push the target equals your Strength modifier.
Published in Player's Handbook 2, page(s) 59.