Thick Club is an item meant specifically for the Pokémon Cubone and Marowak. When held, it doubles the user's Attack stat. Its sprite is identical in appearance to that of Rare Bone.
Ways to Obtain
In all of the Generations since its introduction, wild Cubone or wild Marowak are the usual sources for finding a Thick Club. In Generation II, the item has a 8% chance of being held by Wild Cubone/Marowak. In all subsequent Generations, the probability is 5%. It can also be attained from the Pokéwalker on the Scary Cave path after at least 4500 steps. In Generation V, a Thick Club can also be found on Route 13.