Marvel Studios is developing an untitled Halloween special for Disney+ that's expected to revolve around Werewolf by Night. Gael Garcia Bernal will reportedly play Jack Russell, but The Illuminerdi is reporting that Nina Price, a.k.a. Vampire by Night, is also set to make an appearance.
In the comic books, Jack's family is cursed with lycanthropy after one of his ancestors crossed paths with a werewolf who had been imprisoned by Dracula. As time passed, Jack went from being a standard werewolf to gaining the ability to transform at will. Becoming an unlikely hero, he'd go on to cross paths with a number of characters, including Moon Knight (during Marc Spector's debut).
Jack also has a niece, Nina Price, who as part of the same cursed bloodline also becomes a werewolf. However, after she was attacked by a vampire, her affliction was altered so that she turns into a blood-sucker once the sun sets and a werewolf at full moon (while remaining human during the day). Another key difference is that Nina transforms fully into a white wolf rather than a typical werewolf.
All of this should lend itself well to this Halloween special, as it also presents Marvel Studios with the opportunity to take a deep dive into the MCU's supernatural lore, something we believe is going to start with Moon Knight and then expand in Blade and multiple other projects.
It's going to be an interesting, weird few years for the MCU and that's no bad thing. We're going to be delving into some unexplored areas of this shared world, while the horror side of the Marvel Universe opens the door to new characters, stories, and major introductions (Ghost Rider!).