Dangerous Beauty - S4.E21

The Brawlers are trapped inside Bakugan Interspace and to make matters worse, Chris and Soon arrive with an injured Sellon, sure that she has changed her ways. Dan agrees to trust her, but Shun was suspicious thinking it was a trick. While the Brawlers fend off an attack, Sellon asks Dan to see her personally and when he did she attacked him and Drago and stole his Key. Shun arrives and chases her but is stopped by Chris and Soon's Bakugan, unaware that Sellon is still evil, allowing Sellon to escape. Sellon gives Mag Mel the Key, but he disintegrates and absorbed her declaring that her will to live would be better served as fuel for his Resurrection. The episode ends with Anubias jumping off a building preparing to battle Dan.