As any true Pokémon fan knows, the franchise has continued to grow and evolve in so many ways throughout its 21-year history. To coincide with the release of its 20th film release, Pokémon the Movie 20: I Choose You!, the list of monsters grows by one.
Watch the latest trailer to I Choose You! above that sees Ash, Pikachu, and the whole gang in another wild adventure. A closer look and you'll see a previously unseen monster named Marshadow around the 0:30 mark. As Comic Book Resources reports, Marshadow is known as a "mythological" creature, which longtime Poké players know means its a monster so rare people consider it a myth.