The Basics of Polymorphing
Polymorphing is just one of a set of related magical effects in the D&D game in which the subject creature assumes a new physical form while retaining its essential identity and abilities. These effects include the alter self spell, polymorph spells (polymorph, baleful polymorph, and polymorph any object), the shape change spell, the wildshape class feature, and the alternate form special quality. The rules that govern these effects are similar.
Though the game lacks terms that deal specifically with polymorphing, the rules for polymorph effects make repeated use of several basic game terms, and it pays to know them:
Special Attack: A unique or unusual ability a creature can use to harm or hinder other creatures.
Special Quality: A unique or unusual ability a creature has that is not offensive in nature.
Extraordinary Ability: Extraordinary abilities are nonmagical. They are, however, not something that just anyone can do or even learn to do without natural talent or extensive training. Effects or areas that negate or disrupt magic have no effect on extraordinary abilities.
Extraordinary abilities often depend on particular physical adaptations that a creature has. Changing form often strips the recipient of some extraordinary abilities, but grants some extraordinary abilities that the assumed form has. In general, when you assume a new form, you lose any extraordinary special attacks and special qualities you have unless you get them from a character class. You usually gain any extraordinary special attacks your assumed form has, but not the assumed form’s extraordinary special qualities. That’s because most extraordinary special attacks are based off gross physical features (such a big, nasty claws and teeth) while extraordinary special qualities tend to be subtler and largely derived from a creature’s essential nature.
Spell-Like Ability: Spell-like abilities are magical. (They’re also the subject of an earlier installment in this series.) A creature usually retains its spell-like abilities when it assumes another form because spell-like abilities are primarily mental in nature. You don’t gain an assumed form’s spell-like abilities when polymorphing or even when using the very powerful shape change spell.
Supernatural Ability: Supernatural abilities are magical but not spell-like. Some supernatural abilities depend on specific parts of the user’s body, but most are derived from a creature’s essential self. When polymorphing, you retain most of your own supernatural abilities, but you don’t gain the assumed form’s supernatural abilities unless you’re using the shape change spell.
When a supernatural ability depends on part of your body that your assumed form does not have, such as a mouth for a breath weapon or eyes for a gaze attack, you lose that supernatural ability when in the assumed form.
Natural Ability: This term is a catch-all for just about anything a creature can do (or characteristic that it has) that is not extraordinary, spell-like, or supernatural. Natural abilities include most speed ratings (some very high speeds are not “natural,” see the section on the alter self spell), mode of breathing (lungs, gills), natural armor and weaponry, general appearance, body type, and the presence or absence of the five basic senses (sight, hearing, touch, taste, pain). When polymorphing, you generally lose your own natural abilities and gain those of your assumed form.