Rusting Fog

School: Transmutation; Level: Alchemist 6, druid 6

Casting Time: 1 standard action

Components: V,S,M (rust from a former metal magic item)

Range: Medium (100 ft. + 10 ft. / level)

Effect: Cloud with 20 ft. radius and 20 ft. height

Duration: 1 round / level

Saving Throw: None; see text; Spell Resistance: No

Source: FoW, pg. 115

A cloud of acidic vapors corrodes any iron-based metal within the area of effect. Ferrous creatures and non-magical iron-based metal suffer 1d6 points of damage per round that ignores hardness and applies even if attended (no save). Non-magical metal armor also looses 1d4 points of armor bonus to Armor Class per round exposed. Magical iron-based items get a Fortitude save to resist each round, using the better of their own saving throw modifier (2 + 1/2 caster level) or their wielder's Fortitude modifier. When an item gets to half its hit points or less, it gains the broken condition. When an item gets to zero hit points, it falls apart into rust shavings.

The caster can direct the cloud each round as a move action, to a maximum of 20 feet per round.