Korel's Hand of Evil
(Enchantment/Charm, Necromancy)

Range:  10 feet per level
Components:  V, S, M
Duration:  1 round per level
Casting Time:  4
Area of Effect:  One creature
Saving Throw:  Negates

In casting this spell, the wizard severs the victim's control over one of his arms (75% chance primary hand, even chance if the victim is ambidextrous), making the victim's hand an independent entity whose only goal is the destruction of the victim.
The hand is almost as intelligent as the victim, and will use the quickest available method for killing or disabling the victim (note that the hand can continue attacking even if the victim is unconscious). For instance, if the victim was carrying a dagger, the hand might grab that and attack. If the victim is weaponless, the hand would attempt to choke instead. The hand would not, however, be able to grab a wand and fire it at the victim, since a wand requires a command word to activate.
With weapons, the hand only uses short weapons, since anything longer cannot be easily turned inward. It attacks with the victim's own THAC0 against the victim's own Armour Class, doing the victim's normal damage, including Strength bonuses. For choking, the hand inflicts 1d4 points of damage each round, plus Strength bonus if applicable (75% of this is temporary damage, but remember that the hand can continue choking the victim even if the victim is unconscious). Each round, if no other action is taken, the victim has a 50% chance of breaking the choke hold (the hand may re-establish it with a successful attack roll). Other attack forms are up to the DM's discretion (bashing plates into the victim's head, etc.).
Even though necromancers generally dislike charm spells, this spell provides many a laugh for them. The material component is fingernail clippings from a zombie.

