Polymorph

From NWNWiki

Polymorphing is the changing of a creature's shape through magic. This is accomplished through spells (polymorph self, shapechange) or feats (wild shape, shifter abilities). Polymorphed creatures retain their own minds but have new physical forms, often with preset strength, dexterity, and constitution scores. If one of these physical attributes is not overridden by the new form, any racial modifiers to that score will apply to the ability modifier but not the ability score while polymorphed. (The character sheet does not reflect the change in modifier).

A favored enemy bonus is based on knowing what the foe is, so if a favored enemy polymorphs into another form, the bonus is denied. Similarly, battle training bonuses are based on shape and size, so depend on an opponent's current form. For example, the bonus from battle training vs. giants is lost against a giant polymorphed into something else, but is gained against any creature polymorphed into a giant.

Polymorphed creatures are unable to use most items, aside from potions. Equipped items are unavailable while polymorphed, although the feat-based polymorphing does allow some properties from equipped items to be retained in the new form.