"Marowak is the evolved form of a Cubone that has overcome its sadness at the loss of its mother and grown tough. This Pokémon's tempered and hardened spirit is not easily broken."
As the Pokedex notes, though Cubone is a rather tragic Pokemon, Marowak is very strong because of it. And in the animes and in the games, Marowak is a very powerful Pokemon. In one instance, it took down all of Team Rocket's Pokemon by itself. It's also one of the Gen I Pokemon that got an Alola form.
Marowak's Basic Attacks are Rock Smash and Mud Slap. While its Special Attacks are Earthquake, Dig, and Bone Club.