Note: This information was taken from TSR's original AD&D adventure, the Temple of Elemental Evil.
When donned, this garment polymorphs
the user into a gargoyle, with effect as the
polymorph self spell. No command word is
used. Items carried are absorbed within the
gargoyle form, unusable. Immunities, flying
ability, and all other gargoyle characteristics
are bestowed. Armor Class is likewise
altered, but is modified by the user's true
Dexterity, magical effects, and protective
devices worn or carried (but excluding modifications
from armor and shield).
The cloak's effects may be produced up to
a maximum of three times per day. The
polymorph occurs within 1 segment after
the cloak is donned, without the sparkling
lights usually accompanying a polymorph.
After the first full turn of use, there is a 10%
chance per turn (cumulative) of the wearer
being mentally changed into a gargoyle as
well. If this occurs, the user either attacks or
flies off (just as would a real gargoyle). Only
a wish or death can then return the victim to
The cloak is easily damaged by any edged
weapon, fire, and other hazards. If the
wearer takes 20 or more points of damage
from such attacks, consider the cloak
destroyed. The cloak may be repaired magically
(via limited wish or similar enchantment)
but not by normal means.
As a final note, other cloaks of polymorphing
may be found. Each is designed to
change the user into one specific creature.
Each confers benefits and hazards in the
manner given above-a full polymorph self
(lacking only the spell's curative effects),
with the given chance of permanent mental
change as well.