Spell Barkskin

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Barkskin (3ed PH)

Transmutation

Level:             Drd 2, Plant 2
Components:        V, S, DF
Casting Time:      1 action
Range:             Touch
Area:              One living creature
Duration:          10 minutes/level
Saving Throw:      None
Spell Resistance:  Yes (Harmless)

This spell makes a creature's skin as tough as bark. The effect grants a +3 natural armor bonus to AC. This bonus increases to +4 at 6th level and +5 at 12th level and up. DMs need to note that similar bonuses do not stack, so this spell will not stack with any natural armor that the recipient of the spell might already have.