Lulu

Lulu is a character of the day who appeared in Three Sides to Every Story!.

Ash and his friends met Lulu as she was retrieving her lost Marill. She introduced herself to them and explained that she lives on a Berry farm with her parents, where they harvest many Berries, including the rare Lum Berry. Lulu's parents were out and wouldn't be home for another two or three days. Lulu decided to have the group stay over for the night so that she wouldn't feel lonely while her parents were out.

During the nighttime, Lulu discovered that her Marill was missing, along with Piplup and Elekid. She and the group went searching for them and found them by a grassy area, battling Team Rocket. Back at the orchard, Lulu gave Ash a box of Berries before the group headed over to Twinleaf Town.

(Source: Bulbapedia)