Night of Blades

Standard Action | V, S | Close | 10 ft/level
1 Minute/level | Reflex half | Yes
You create an immobile wall of tiny black blades that whirl and tear into creatures like a cyclone. Anyone who enters this space takes 1d4 points of damage per caster level (maximum 10d4), though
a successful Reflex save halves the damage. The spell cannot be cast so that it appears in a space already occupied by Small or larger creatures.