Return to the Earth

''Throwing dust at the body and uttering a prayer of destruction, you make the creature wither and decompose at an unnatural rate. It dries to become a lifeless husk before it decomposes into dust.''

You can decompose a body just by casting dust or earth at it. You need to spend 4 rounds to decompose a Medium corpse. (Double the time required for each size category larger than Medium; halve the time for each size category less than Medium, to a minimum of 1 round). Corpses decomposed by this spell can still be restored to life, but cannot be turned into undead.

You may throw earth or dust as a ranged touch attack (maximum range 10 ft., no range increment); the earth deals 1d12 points of damage to corporeal undead and constructs that are composed of dead flesh or bones.