Flegias

Da SRD http://www.d20srd.org/srd/spells/shapechange.htm This spell functions like polymorph, except that it enables you to assume the form of any single nonunique creature (of any type) from Fine to Colossal size. The assumed form cannot have more than your caster level in Hit Dice (to a maximum of 25 HD). Unlike polymorph, this spell allows incorporeal or gaseous forms to be assumed.