Shapeshifting Mastery (Ex)

Your ability to magically adopt other forms is unparalleled, and you can expertly translate your arcane might into brawn. You add half your tier to the caster level of spells or extracts from the polymorph subschool. While under the effects of a spell or extract of the polymorph subschool, you can use your caster level instead of your base attack bonus when making natural attacks that rely on your new form.