Necromancy
Level: Druid 4, Sorcerer 5, Wizard 5
Components: V, S
Casting Time: 1 standard action
Range: 30 feet
Target or Area: 30-ft. cone-shaped burst or one solid object; see text
Duration: Instantaneous
Saving Throw: Fortitude half or Will negates (object); see text
Spell Resistance: Yes (object)
A red mist rises from the ground as you intone this spell, billowing outward from you. Within it you see leaves curl up, scrolls rot from their spindles, and the leather armour of your foes drip from their vulnerable forms.
Miasma of entropy causes accelerated decay in all wood, leather, and other natural materials in the spell’s area. It destroys non-magical objects of wood, leather, paper, and other formerly living organic matter. All such objects within the area rot into slimy, pulpy masses. Objects weighing more than 1 pound per caster level are not affected, but all other objects of the appropriate composition are ruined.
Alternatively, you can target miasma of entropy against a single solid object of non-living non-magical organic matter that weighs up to 10 pounds per caster level.
Source: Spell Compendium (Page 141)