Bone Club

Answer "Nothing, A River, Fear, Memory" to apparitions in Spellhold dungeon level 3 and get teleported to Momentary Relapse, kill the trolls, place Giant Troll's Head, then take Bone Club from the altar.

In-game description
"This vicious club was created hundreds of years ago, reportedly by a shaman on a quest for revenge. His family had fallen to undead, and so personal was his rage that he amputated his own leg, using the femur for the body of the weapon. Magical runes empower it, though it is likely the sheer force of the shaman's hatred would have served on its own."