Evil Dead The Musical is making its debut at the Iowa City Community Theater tomorrow, and that fact has left everyone I’ve mentioned it to with one question: “Wait, that’s a musical?”

I understand the confusion. For those of us who don’t have a Broadway obsession, the idea of combining horror and musicals is a strange one. Musicals have a reputation for being bright and cheery, full of tap-dancing and triumphant group numbers, while horror’s reputation is one of doom and gloom.

But in reality, it’s not a question of whether musicals and horror can mix — spoiler alert, they definitely can — but rather a question of how to mix them successfully.

In 1979, Sweeney Todd: The Demon Barber of Fleet Street won eight Tony Awards, including “Best Musical.” In 2007, it was adapted into a movie starring Johnny Depp and Helena Bohnam Carter, which won several awards of its own.

The story follows a vengeful barber and a cannibalistic baker, and, as you may have guessed, it’s not exactly a heartwarming story. Unless you count Mrs. Lovett literally warming hearts by putting them in pies and sticking them into the oven, that is.

Yet, it’s one of the most critically acclaimed musicals of all time, as well as one of the most popular amongst audiences.

The key to making Sweeney Todd work as a horror story and a musical lies in its songs. The music and lyrics were written by Stephen Sondheim, which is obvious to any Sondheim fan upon first listen.

Sondheim is a master at fitting complex lyrics into his songs. If a character is singing a mile a minute, it’s probably Sondheim. His lyrical mastery grants audiences a deeper look into the psyche of the demon barber himself, which is essential to make a successful horror musical.

In horror movies, killers can rely on special effects to seem scary, but, in most cases, musicals are performed live. Stage effects have come a long way, but Sweeney Todd premiered in 1979, and the movie version made a point of leaving realistic special effects out. In fact, the blood used in the movie is orange.

The horror of Sweeney Todd doesn’t come from murder itself, but from the mind of the murderer. He’s a vengeful, calculating, cold-blooded killer with a seriously creepy aesthetic and some major anger issues, yet you find yourself rooting for him along the way.

And it’s not because he has any likable personality traits, because he definitely does not. It could be argued that we root for him because of his tragic backstory, which isn’t exactly untrue, but the real reason Sweeney Todd is so easy to cheer on is because when he’s singing about murder and revenge, you truly understand him.

Sweeney Todd is far from the only horror musical character who commits horrific acts that we still find ourselves sympathizing with. Carrie from Carrie the musical kills her entire class, Seymour from Little Shop of Horrors feeds his love interests’ ex to a giant plant, and the Phantom from The Phantom of the Opera hangs a man and kills who knows how many others for disobeying his demands.

Whether or not you agree with their actions is irrelevant. It’s coming to the realization that you went inside a killer’s head and came back out not only understanding them, but sympathizing with them that will keep you up at night.

In a horror movie, the appeal comes from rooting for the good guys as they run for their lives. In a horror musical, the appeal comes from seeing into the minds of the characters, and realizing that maybe there’s the potential to become a killer in all of us.