I had a dream about Pokemon Sun and Moon leaks in mid November. Usually I don't dream about this stuff, but whenever I do it ends up surfacing one way or another. Two previous dreams I've had were in the ORAS hype season, where the Battle Frontier was confirmed NOT to be in the game and /vp/ lost it's shit, which ended up being true and spoiler]a Mega Flygon "leaked" but ended up being fake. It was a SSBB Ridley render recolored to look like Flygon. About a day later, the same image I've described surfaced as a joke post.

Anyways the leaker was Japanese, so the leaks were in Japanese too. There is an item that allows you to add a type to a Pokemon, allowing for Triple-Typed Pokémon (it might've been the same items used for Type Null's evo).

The second part is far more fascinating. Arceus appears in a form that looks like a fusion of all known legendaries. It has all the types at once, and its only weakness is Rock. In Japanese it is known as "Dark Arceus". It serves as the final boss for the Main Story. You cannot catch it or receive it legitimately in game, you must defeat it. However regular Arceus is made obtainable in the post game. The battle takes place on a floating Spear Pillar in what looks like a portal in space. The leaker was using a Flygon in his battle against Dark Arceus.