Here's another one, I just made up. Comments welcome.

Hammer of Oervel

This device is in the hands of Oervel Devlyn (MA; F1; Ma, tainted 1; LN), who
had it made because he had the extremely bad luck of always getting mugged by
the thief's guilds of Mhowe. It was created by an acquaintance, Meganno the
Socerer, one of the Three Brother Mages. He wanted something to defend
himself, but got something much more. The hammer has a shale grip, a shaft of
walnut wood, and a head of sandstone, with jagged adamantite points
(1d2+1/1d2). Additionally, the hammer has the power to polymorph anyone it
strikes into a small harmless animal, such as a pig or cat. However, the
hammer is also semi-sentient and can communicate by telepathy. Meganno made
one minor error when creating the hammer, however. Due to this error,
everytime the hammer is used, the wielder must succeed a wisdom check, or lose
a point of wisdom. Oervel, a competant construction worker is now saving up to
get out of the Chimaeron, & create a better life.