A Chardalyn arm imbued with a fixed charge of spells. It is practical, vicious, and carved intricately with residuum circuits. Theoretically, a very large number of spells can be loaded into the arm ahead of time (up to 16 levels), though it is very expensive and time consuming to do so.
This arm can be attached to the body and used to cast the spell Gravitational Sinkhole at 4th level 3 times (it needs to be recharged by spending a week, 200 GP, and a DC 17 arcana check to restore 1 charge.) - Additionally, it gives the wearer a +1d4 to grapple checks made with it, and a claw attack that deals 1d6 slashing.