At the beginning of the month, Nintendo and Game Freak revealed the Alola Forms for some of the original 150 Pokémon. Earlier today, more of these Pokémon were leaked via the Pokémon board on 4chan. Below is the trailer showing off Alola Raichu, who can see seen surfing on his tail, and has been upgraded to an electric and psychic-type Pokémon, and is sporting a sick tan. Since this is leaked footage, you can expect the video to be taken down fairly soon.
Also leaked is a new Pokémon named WishiWashi whose ability transforms it into a larger Pokémon by gathering a school of fish. See it in action here:
Below are more of the leaked images.