The Oval Charm is a key item found in the later Pokemon games. Originating in Pokemon Black and White, the Oval Charm is used to increase the chance of finding an egg in the Pokemon Day Care Center.
As long as you have this item in your bag, its effect will be active even when not held by a Pokemon.
This item is an essential piece to perform Mass Hatching, wherein you have to determine which Pokemon has a good IV from a batch of eggs. Mass Hatching will take much longer if you don’t have this key item.
How to get the Oval Charm
You can get the item by defeating Morimoto (a member of Game Freak) inside the Game Freak office in Heahea City. After completing the main story, head to the Game Freak office found on the second floor of Akala Island’s Pokemon Center. Morimoto is standing at the back wearing a gray outfit with blue highlights.