Shapechange

Shapechange is a transmutation spell. A powerful variant of the polymorph family, it changes the user's shape into any creature, and allows him/her to change again once per round.

Effects
As polymorph other, except this spell enables you to assume the form of any single creature of less than deity status (including unique dragon types, or the like) or any single object. The assumed form can be no smaller than a flea and no larger than 200 feet in its largest dimension. Unlike polymorph other, this spell allows incorporeal forms to be assumed.

Your new form works like a polymorph other form. You still do not gain the supernatural or spell-like abilities of your new form, though you do gain its extraordinary abilities while keeping your own. You also gain the type of the new form (for example, "dragon" or "magical beast") in place of your own. The new form does not disorient you. Parts of your body or pieces of equipment that are separated from you do not revert to their original forms. Thus, a new form's poison bite is effective.

You can become just about anything you are familiar with. You can change form once each round as a free action. The change takes place either immediately before your regular action or immediately after it, but not during the action. For example, you are in combat and assume the form of a will-o-wisp. When this form is no longer useful, you change into a stone golem and walk away. When pursued, you change into a flea, which hides on a horse until it can hop off. From there, you can become a dragon, an ant, or just about anything you are familiar with.

If you use this spell to create a disguise, you get +10 on your Disguise check.

Material components
A jade circlet worth no less than 1,500 gp, which you must place on your head when casting the spell. (The focus melds into your new form when you change shape.)