Melf's Acid Arrow

Conjuration (Creation) [Acid]
Level: Sor/Wiz 2
Components: V, S, M, F
Casting Time: 1 standard action
Range: Long (400 ft. + 40 ft./level)
Effect: One arrow of acid
Duration: 1 round + 1 round per three levels
Saving Throw: None
Spell Resistance: No

A magical arrow of acid springs from your hand and speeds to its target. You must succeed on a ranged touch attack to hit your target. The arrow deals 2d4 points of acid damage with no splash damage. For every three caster levels (to a maximum of 18th), the acid, unless somehow neutralized, lasts for another round, dealing another 2d4 points of damage in that round.

Material Component
Powdered rhubarb leaf and an adder's stomach.

Focus
A dart.