As part of its ongoing efforts to promote every single Pokémon out there, The Pokémon Company has shared special content dedicated to Graveler:
Did you know? It climbs up cliffs as it heads toward the peak of a mountain. As soon as it reaches the summit, it rolls back down the way it came. It travels by rolling down cliffs. If it falls into a river, it will explode with its last gasp.
Source: The Pokémon Company