Joe Locke as Teen, Aubrey Plaza as Rio Vidal, Kathryn Hahn as Agatha Harkness, and Sasheer Zamata as Jennifer Kale in "Agatha All Along."Chuck Zlotnick/Marvel StudiosThe "WandaVision" spinoff "Agatha All Along" premieres on Disney+ with two episodes on Wednesday.The Marvel series stars Kathryn Hahn as a witch named Agatha Harkness.Business Insider has previewed the first four episodes.