Madeleine

Madeleine is a character of the day who appeared in Clamperl of Wisdom who lives on Maisie Island. She did not have a name in the original version.

While walking with her Pokémon, a Spoink Psychically placed her Shroomish on its head after it had lost its pearl. May immediately returned Shroomish to her with apologies, and the two promptly ran away.

Later, while walking along the shore, Madeleine and her friend encountered the Spoink again. They held their Pokémon away from it, afraid that it would take their Pokémon again. Though they were relieved to see that Spoink had a blue pearl atop its head. Spoink suddenly fell, sending its blue pearl ricocheting through some rocks and being swapped by a Clamperl's pink pearl in the process. The pair reported the incident to Ash and his friends, pointing them to the Clamperl.

(Source: Bulbapedia)