[Bozos of Bones]

Any weapon that deals bludgeoning damage. There are three types of physical damage: piercing, bludgeoning and slashing. Maces, staves, fists, flails, hammers and slings all deal bludgeoning damage.
If you can't kill him with these, you can lure him under the three rock traps and crush him there.
And in the future, try using the search function, this topic has been addressed countless times before.