Tales From the Underworld: A Knight with Cruella

"Tales From the Underworld: A Knight with Cruella" is a canon bonus feature on the fifth season DVD for Once Upon a Time

Summary
Set in the Underworld and featuring Cruella and an all-new Once Upon a Time character portrayed by a special, surprise actor (James Marsters). Cruella has been left behind in the Underworld at the end of the season, and we didn’t exactly learn her fate... until now.