Skipping a monster today, and going back to one of the shields from Dragon Magazine #89.
Unique magic armor (shield)
Named for the fighter who found it in a dragon’s hoard, this shield was later sold to King Osbrun of Chessagol, whose treasury and armory were looted six winters ago, some say by magic. The Protector vanished
in that theft, and its present whereabouts and owner are unknown. This shield is a plain, battered, kite-shaped construction of bronze plates bolted to a sturdy wooden frame. It bears no maker’s-mark or inscriptions. It is magical, and has the following powers and abilities:
Any damage that pierces or parts the bronze plates, or cracks through or breaks the wooden frame, is magically mended overnight. Minor dents, scratches, and scars are not so repaired. Manual repairs by a blacksmith or by you seem to have no effect on the shield.
The Protector has all the powers of a ring of protection, giving you a +1 to AC and to saving throws. In addition, whenever you rap the wooden frame of the Protector three times rapidly with a finger or knuckles, the shield will radiate and maintain, through some unknown magical means, a 10’ radius globe of air, cool and breezeless. This globe will withstand the pressures of deep water, gusts of wind, and the like without altering its shape or location, remaining centered upon the Protector. Large, solid, immobile objects like stone walls will cause the “air bubble” to flatten out along the wall or around the object. Creatures within the globe of air cannot drown, suffer harm from poisonous vapors, etc. As many creatures can be protected by the globe as can fit into its area, usually 40 or so, or, if freedom to move and fight is required, 8 or 9 man-sized beings. The air supply can never be “overloaded” or used up.
Most creatures are not physically constrained from entering or leaving the sphere. It seems to keep out only creatures who cannot breathe or move in air (such as living fish), and those who are gaseous in
form (air elementals, a vampire in gaseous form, etc.). The globe of air persists until the bearer again raps the wood frame thrice; to be effective, such rapping must be on the inner side of the shield, directly on the frame, and the bearer must have the shield slung on his arm or strapped to him.