Swosh in Yo-kai Watch 2

Take on the quest "The God of the Sea" at Little Haven Station. This quest only appears in the daytime. Go to the shrine in San Fantastico and wait until dawn. Encountering the shrine right before dawn makes Swosh come out and fight the player. After the player beats him, the quest will be completed. After, wait a day, and go to the shrine right before dawn again. The player should be able to fight him once a day/soft reset and befriend him through normal means.