This Mawile is a steel/fairy-type Pokémon owned by Count Pumpka.
When Jessie tricked Count Pumpka into trapping Ash and his friends in a cage, Count Pumpka aoffered a trade for his Mawile for her female super-sized Pumpkaboo. Unfortunately for Jessie, she accepted the trade in hopes of Mega-Evolving Mawile in the future. When the trade was finished, her Pumpkaboo immediately evolved into Gourgeist, which caused Prince Pumpkaboo to lose complete interest in her. Upon seeing how Pumpkaboo's trade triggered the evolution, Jessie changed her mind and she and Count Pumpka traded their Pokémon back.