Bone Club

This spell enchants a bone, causing it to become a magical club. This magical weapon acts as a club +4 against undead, inflicting d6 +4 hit points of damage, and a club +1 against all other opponents, inflicting d6+1 hit points of damage.

The bone can be from any animal, providing the bone normally could be wielded as a club; for instance, a human femur could be enchanted by this spell, but a skull could not. At the end of the spell's duration (1 round per level), the bone club reverts to a normal bone.

Characters who are proficient with a club also have a proficiency with a bone club.

(transcribed from the 2e Wizard's Handbook)