BW025: Battling for the Love of Bug-Types!

Synopsis
After the events of the last episode, Ash finally has his battle with Burgh at the Castelia Gym. Meanwhile, though disbanded, Jessie, James and Meowth search for their boss Giovanni. James finds a Yamask and feeds it. After this act of kindness, Yamask is caught by James. During the Gym Battle, Ash's Sewaddle evolves into Swadloon and with it, Tepig and Pikachu, Ash wins the battle and the Insect Badge.

Trivia

 * This is the first episode where a main character's pokemon evolves during a Gym Battle.
 * This episode was supposed to air two weeks later but was bumped yp after "Team Rocket vs. Team Plasma"'s delayment.