Shadowblast

Evocation [Light]
Level: Cleric 4, druid 4
Components: V, S, M
Casting Time: 1 standard action
Range: Long (400 ft. + 40 ft./level)
Area: 20-ft.-radius spread
Duration: Instantaneous
Saving Throw: Fortitude negates
Spell Resistance: Yes

Light flashes bright and white for an instant in the area of this spell, dispersing portals to the Plane of Shadow and stunning the unnatural creatures that fear the light.

Natives of the Plane of Shadow caught in a shadowblast are stunned for 1d6 rounds if they fail a Fortitude saving throw. Shadow natives that are also undead or vulnerable to light take an additional 2d10 points of damage if they fail a second Fortitude save. Creatures that fail either Fortitude save cannot use spell-like or supernatural abilities to open any portal to the Plane of Shadow for 3d6 minutes.
Shadowblast closes all portals, gates, and other openings to the Plane of Shadow in its area. Creatures on the other side of a portal are unaffected by shadowblast.

Material Component: A handful of grave dirt, squeezed tightly and flung.