When this spell is cast, the wizard is able to assume the form of any
creature, save those that are noncorporeal, from as small as a wren to as large as a
hippopotamus. Furthermore, the wizard gains its physical mode of locomotion and
breathing as well. No system shock roll is required. The spell does not give the
new form’s other abilities (attack, magic, special movement, etc.), nor does
it run the risk of the wizard changing personality and mentality.

When the polymorph occurs, the caster’s equipment, if any, melds into the new
form (in particularly challenging campaigns, the DM may allow protective
devices, such as a ring of protection, to continue operating effectively). The caster retains all mental abilities,
including spell use, assuming the new form allows completion of the proper
verbal and somatic components and the material components are available. A caster
not used to a new form might be penalized at the DM’s option (for example, -2
penalty to attack rolls) until he practices sufficiently to master it.

Thus, a wizard changed into an owl could fly, but his vision would be human; a
change to a black pudding would enable movement under doors or along halls and
ceilings, but not the pudding’s offensive (acid) or defensive capabilities.
Naturally, the strength of the new form is sufficient to enable normal movement.
The spellcaster can change his form as often as desired for the duration of the
spell, each change requiring a round. The wizard retains his own hit points,
attack rolls, and saving throws. The wizard can end the spell at any time; when
voluntarily returning to his own form and ending the spell, he regains 1d12 hit
points. The wizard also will return to his own form when slain or when the
effect is dispelled, but no hit points are restored in these cases.