A new video has been uploaded to YouTube that has revealed more information about Meltan and the means of acquiring it in Pokémon Go.
Pokémon Go players from all around the world have been seeing a new Pokémon with a metallic body and a nut for a head. A video released on the official Pokémon YouTube channel shed some light on the subject, as Professor Oak and Professor Willow discovered that the Pokémon is called Meltan and is somehow related to Ditto.
It seems that you will need to find a Mystery Box in Pokémon Let's Go Pikachu & Let's Go Eevee and send it to your character in Pokémon Go. This should summon a group of Meltan, though the trailer suggests that you have a limited amount of time in which to do so, as the Mystery Box doesn't stay open for long.
This method of acquiring Meltan will likely be necessary for capturing it in Pokémon Let's Go Pikachu & Let's Go Eevee as well, as you will probably need to trade one from Pokémon Go to your Let's Go character.
There was also a video reveal that showed Meltan in a live-action setting, which shows a silhouette of a creature that is presumably the evolution of Meltan.
The method of acquiring Meltan is similar to a scrapped concept from the Pokémon games that appeared on the Nintendo DS.
In the files of Pokémon HeartGold & SoulSilver, there is a dummied item called the Lock Capsule, which has no use and cannot be opened. The intention behind this item was that you would be able to trade the Lock Capsule to a Pokémon Black & White player using the Relocator, where a person in the Unova region would be able to unlock it, which would give you the TM for Snarl.
It's still not known why the Lock Capsule was never used in Pokémon HeartGold & SoulSilver, but the concept behind it is being reused with the Mystery Box in Pokémon Let's Go Pikachu & Let's Go Eevee.
Pokémon Let's Go Pikachu & Let's Go Eevee will be released for the Nintendo Switch on November 16th.