One day, as Marowak tended to its baby, a Cubone, two Team Rocket members came to abduct some Pokémon. Marowak hit the grunts using its bone, allowing Cubone to escape. However, the grunts were furious and attacked Marowak, a scene which Cubone saw.
Marowak started to haunt the tower in Lavender Town, scaring off everyone. Red used his Silph Scope and identified the ghost to be Marowak. Cubone came to Marowak's ghost, who hugged her child and passed on, her spirit calmed down.
None of Marowak's moves are known.