I figured that Giratina was in Origin Form in Wispy Tower due to the spiritual energy surrounding Goldenleaf Town. We know that its built on top of Griselda's old kingdom, so it's probably connected to the Distortion World. Cubone can also evolve into Alolan Marrowak, and there are lots of ghost types in the grass, so maybe these are the spirits of the people from Griselda's kingdom