Gengar can enter Gigantamax mode in Pokémon Sword and Shield. According to the Pokémon’s Pokédex entry in Pokémon Sword, “It lays traps, hoping to steal the lives of those it catches. If you stand in front of its mouth, you’ll hear your loved ones’ voices calling out to you.” Would never, EVER want to cross paths with something like that! Pokémon Sword and Shield are available now, exclusively for Nintendo Switch.
Source: Polygon.com