Polymorph
Many problems with this spell made it a perfect target for change. Not only did it have multiple printings and clarifications but it was one of the first spells banned from organized play (something I didn't know). The new poloymorph which works on willing targets always a transformation into a living creature (including aberration, animal, dragon, fey, giant, humanoid, magical beast, monsterous humanoid, ooze, plant or vermin). There are HD caps (caster level up to 15). You get the physical characteristics of the creature but not extraordinary, supernatural or spell-like abilities with the exception of extraordinary attack forms. The example given is the polymorphed fighter that is now a troll: he gains the strength and rend characteristics but not regeneration. The spell lasts one minute per level.