Pokemon Let’s Go and Super Smash Bros. Ultimate are Nintendo’s big holiday titles. If you have both games, and a save file for the former, then you will unlock a little surprise in Smash Ultimate. If you have Pokemon Let’s Go Eevee, you can unlock the Partner Eevee Spirit. Owning Pokemon Let’s Go Pikachu unlocks Partner Pikachu Spirit. If you don’t have Pokemon Let’s Go, don’t worry. You can still unlock them by completing challenges. An official tweet about the matter can be seen down below.