The Japanese magazine explains that when Type: Null discovers a Trainer that it trusts, it will destroy its helmet and evolve into Silvadi.
Silvadi is a Normal-type Pokémon but it can hold a special item called Memory that will let it become any one of all 18 types at will thanks to its ability, AR System.
Serebii reports that it is not clear whether it is a single Memory item that can change this, or if Trainers will be required to collect 18 different ones.
The chosen type is reflected in Silvadi’s eyes, mane, and tail, which will glow with the colour that represents the type. It has a new move called Multi Attack, which will change type based on the item held.
Pokémon Sun and Pokémon Moon will release exclusively for Nintendo 3DS in North America, Australia and New Zealand on November 18th, and in Europe on November 23rd.