Universal Studios Hollywood will bring dozens of characters from “Harry Potter,” “Star Trek,” “Back to the Future” and Dungeons & Dragons to a new after-hours fandom event that promises to be a cross between Halloween Horror Nights and Comic-Con.

Universal Fan Fest Nights will run various nights between April 25 and May 18 at the Hollywood theme park. The new separate-admission, after-hours events will be dedicated to science fiction, fantasy, gaming and anime. A casting call for auditions held recently revealed dozens of characters that will make appearances during Fan Fest, according to Universal Parks News Today.

The “Back to the Future” casting call was seeking actors to play the roles of Marty McFly, Emmet “Doc” Brown, George McFly, Lorraine McFly, Lorraine’s friend, Biff Tannen, Biff’s sidekick, Principal Strickland, Goldie Wilson and the Clocktower Lady. The “Back to the Future” franchise was shot on the Universal back lot — suggesting a studio tram trip to Courthouse Square could be part of Fan Fest. The site of Simpsons Ride at Universal Studios Hollywood once housed Back to the Future: The Ride. The DeLorean car from the trilogy has been featured at the park.

The “Star Trek” auditions were looking for actors to play the human crew members as well as fictional species and extraterrestrials from the science fiction franchise — including Vulcan, Orion, Trill, Efrosian, Andorian, Bajoran and Elayisan.

An original set piece of the USS Enterprise bridge from the “Star Trek: Picard” television series will be a highlight of Fan Fest. Universal Studios Hollywood was once home to live action show “Star Trek Adventure.”

The actor playing Xanathar the Beholder from the Dungeons & Dragons franchise will need to be able to push and pull a 30-pound puppet creature, according to the audition notes.

Wizards, monsters and treasure hunters will come to life in the Dungeons & Dragons experience at Fan Fest. The D&D activation will celebrate the 50th anniversary of the role playing game, 2023 film “Dungeons & Dragons: Honor Among Thieves” and video game Baldur’s Gate 3.

Magical creatures will pop up in the Wizarding World of Harry Potter, with the sweet but destructive Niffler the only confirmed critter so far for Fan Fest. A Niffler puppet sitting on a pushcart at the Owl Post has made regular appearances at Wizarding World at Universal Studios Japan.

Universal Fan Fest will also feature anime props from “One Piece” — a Japanese manga series that follows the adventures of Monkey D. Luffy and his Straw Hat Pirates on their quest to find a legendary treasure.

The Fan Fest casting call sought actors to play “One Piece” characters Luffy, Sanji, Usopp, Nami and Zoro. Universal promises to “nurture and celebrate” Trekkies, Potterheads, McFlyers, Dungeon Masters and other fandom communities obsessed with the movies, TV shows, books and games associated with the intellectual properties.

The fest promises activations and live entertainment from the creators of Halloween Horror Nights, along with cosplay, themed food and merchandise.

Some theme park attractions will also be open during Fan Fest — including Harry Potter and the Forbidden Journey, Transformers: The Ride 3D, Revenge of the Mummy roller coaster, Jurassic World — The Ride and the Simpsons Ride.

The fest will be held April 25-27, May 2-4, May 9-11 and May 16-18. Tickets are expected to go on sale in the next few weeks.