Earlier this month, Game Freak dropped a few hints about a second form for the Mythical Pokémon Meltan. An ominous shadow was shown at the very end of Professor Willow’s Meltan Research Update. We now know that this shadow was actually Melmetal, Meltan’s evolved form.
Melmetal is, like Meltan, a pure Steel-type Pokémon. It looks much larger than Meltan, with its liquid metal congealed into something giant and roughly Donkey Kong-shaped. Because Meltan evolves into Melmetal, this means that Meltan is officially the only Mythical Pokémon to be able to evolve thus far.
Meltan is also unique in the way it evolves. Kind of. Meltan can only evolve into Melmetal in Pokémon GO, and there is no way to evolve it in either Pokémon: Let’s Go title. Meltan candies can be obtained the same way players obtain candies for other Pokémon. Once players evolve Meltan by giving it 400 Meltan candies, only then can players transfer and use Melmetal in the console Pokémon titles.
Pokémon: Let’s Go, Pikachu! and Let’s Go, Eevee! will be released on November 16, so get ready to collect lots of Meltan candies!
Source: Nintendo Everything