Ben 10: Season 3, Episode 22

3 - 22: King of the Castle

Team Tennyson finds out about their British ancestry, so they visit their relative's estate, but mysterious events convince Ben that the place is haunted. However, it turns out that Kevin Levin has followed them, and showcases three new forms based on those Ben has lost: Thornblade, Undertow, and Dark Matter. How will Ben defeat the corrupted versions of aliens he can no longer use?