Rolling Stone (4e Power)

Rolling Stone	Explorer Attack 3
You conjure a large stone that crushes your enemies.
Encounter Primal, Conjuration, Implement
Standard Action	Ranged 20
Primary Target: One creature in range.
Attack: Wisdom Vs. Reflex
Hit: 2d8 + Wisdom modifier damage, and the target is knocked prone. You conjure a 4-by-4 squares large stone based on the target square. You then push the stone squares equal to your Dexterity modifier to any direction. Each time the stone enters an occupied square, make the following attack. The stone dissapears after the movement.
Secondary Target: One creature in the stone's space.
Secondary Attack: Wisdom Vs. Reflex.
Hit: 1d8 + WIsdom modifier damage, and the target is knocked prone and pushed 1 square away from the stone's space.