Caustic Weapon
From HGWiki
Caster Level(s): Assassin 1; Druid 3
Innate Level: 1
School: Conjuration
Descriptor(s): Acid
Component(s): Verbal, Somatic
Range: Touch
Area of Effect / Target: Creature or Melee Weapon
Duration: 1 Minute / Level
Additional Counter Spells:
Save: Harmless
Spell Resistance: No
Description: Coats a melee weapon with Acid adding 1 die of Acid damage, increasing to 2 dice at caster level 16, 3 dice at caster level 31, and 4 dice at caster level 46. This damage stacks with permanent damage bonuses already on the weapon. You can target a specific weapon or a creature (if said creature is holding a weapon). You can target a specific weapon or a creature with this spell. This spell can't be cast on character more than 6 levels below the caster's level and disappears when the weapon is transferred.
Notes
If the weapon is dropped or converted into slag, disarm, or any other token the spell disappears.
This spell will auto-recast when the duration expires if the caster still has unused copies in his memory, if the caster and the recipient are in different areas the spell effects will gradually degrade until they completely dissipate.