You cast this spell on any wooden-hafted two-handed weapon (such as a greataxe or heavy flail) or any wooden-hafted reach weapon (such as a longspear or glaive).

The next time that weapon is used to make a melee attack, its shaft twists around so that the weapon strikes the wielder instead, with the attack roll applied against the attacker's own AC.

The wielder gets no warning or knowledge of the spell's effect on his weapon, and though he makes the attack, the self-dealt damage can't be consciously reduced (though damage reduction applies) or changed to nonlethal damage.

Once the weapon attacks its wielder (whether successfully or not), the spell is discharged.

The spell can target a weapon of any size as long as its wielder normally uses it as a two-handed weapon or a reach weapon.

For example, a Small longspear wielded by a halfling could be the target of the spell, but not the same Small longspear wielded by a human; in the human's hands, the weapon is too small to twist around and strike its wielder.

Magic weapons targeted by this spell receive a Will save.

An item in a creature's possession uses its own Will save bonus or its wielder's bonus, whichever is higher.