It seems that the type of Pokemon summoned by a slate determines the shape of the slate. The Genome Slate, for instance, which summons Mewtwo in the Genome Room of Ramanas Park, takes the form of a GB cartridge, likely because Mewtwo first appeared in Pokemon Blue and Red on the GB...
Related:Pokémon BDSP: How To Find (& Catch) Groudon, Kyogre, and Rayquaza In order to find and capture Mewtwo, players will need to have defeated Raikou, Entei, Suicune/Articuno, Zapdos, Moltres, Latios, and, Latios. The legendary trio is dependent on which version the player owns. Playe...