The Mystery Gang from the Scooby-Doo Where Are You! franchise is a cultural staple for animation’s “who done it” genre. Starring young friends Fred, Daphne, Velma, Shaggy, and Scooby, viewers were treated to an episode-by-episode mystery since its creation in 1969, created by Joe Ruby and Ken Spears. From there, there have been several iterations of the show in the form of spin-offs and live-action films. Throughout every version, the running gag has been in that final unmasking, where the villain underneath the monster costume is just the angry form of someone looking for revenge. Inevitably, the mask always comes off.

Nevertheless, in Jim Stentrums’s 1998 Scooby-Doo on Zombie Island, a notable shift in tone and aesthetic departs from its source material. In this film, the mask doesn’t come off. The film deviates from that lore of final “unmasking,” revealing a culprit. Here, the horrors and plastic monster costumes become very real. Two things suggest why this film remains so crucial to the conversation of horror in animation: its complete shift in aesthetic choices and the transformative maturity of its lead characters. The pivot from the show’s and other films’ more childlike aesthetic and narrative choices to a more ominous take resulted in the film’s longevity.

Set in the sweltering and eerie bayous of New Orleans, Louisiana, the gang reunites to help Daphne Blake, voiced by the late Mary Kay Bergman (South Park), unearth some of the most frightening haunted sites for her show, “Coast to Coast with Daphne Blake.” Despite the countless visits to several alleged haunted places, it isn’t until the gang lands in New Orleans that they catch their first big lead. In a chance meeting, the gang is invited back to Moonscar Island by a woman who works there, Lena Dupre, voiced by Tara Strong (The Fairly OddParents). With the promise of visiting one of the most haunted areas in all of Louisiana, the gang sets out to uncover its most sinister origins.

Werecats_(Zombie_Island)

What ensues is a chilling path down an actually haunted island filled with a violent history. The gang doesn’t know that Lena and the homeowner there, Simone Lenoir, voiced by Adrienne Barbeau (The Fog), were the sole survivors of pirate Captain Moonscar’s violent attack on their land. After escaping, Lena and Simone prayed to their cat god to curse Moonscar. They turned into werecats, killed the pirates, and condemned themselves in granting their wish. To remain immortal, they had to drain the lives of humans every harvest moon. In doing so, they’d trap the souls and keep them prisoners on the island.

RELATED: 8 Cartoons Horror Fans Are Sure to Love

All these elements of voodoo, curses, and zombies translate into the visual nature of the animated film. Most of the colors are grungy and dull in tone, matching the darker nature of the narrative. Aesthetically, the choices were those in most live-action horror films like Train to Busan or The Last Day. With its gloomy and dingy look, disorienting animation and characters’ movements, and grotesque depictions of wolves, the film lends itself to be the most terrifying yet. Some of the camera movements themselves are often shaky and jarring for viewers, depicting images of disorientation and panic.

Elements like carvings on the wall resembling “REDRUM” from Stanley Kubrick’s The Shining, depictions of violence, the actual use of mystical creatures like werewolves, depart from the regular format of the series and other films. Even in its live-action depictions of Scooby-Doo, there wasn’t as much emphasis on the “horror” of the plot as there is in this film. Even the point-of-view shots of Fred Jones’s camera, voiced by Frank Welker (The Jetsons), is a callback to the found footage element of horror films like Daniel Myrick and Eduardo Sánchez’s The Blair Witch Project. By referencing some of these horror films in the film’s aesthetic makeup and making its own, Scooby-Doo on Zombie Island is leaving behind its mark in the horror genre.

Nuance is also in the new depictions of its main characters. Viewers no longer find themselves with young, idealistic kids from the original series. In Scooby-Doo on Zombie Island, audiences find Daphne and Fred pursuing a career in telecasting; Scooby, voiced by Scott Innes (Scooby-Doo) and Shaggy, voiced by Billy West (Futurama), working low paying jobs at an airport; and Velma Dinkley, voiced by B.J. Ward (Voltron), working a menial bookshop job. This is now the grown-up Mystery Inc, leading the life of any adult of their time: some with flourishing careers and others with not-so thrilling ones. The film understood that these kids needed to grow up to create a scenario where the gang is fighting authentic magic and zombies in the middle of a deserted swamp.

Watching the gang in a grown-up setting only added to the realism of the plot. To the real threat of danger. This was no longer kids solving mysteries of corrupt people. These are not adults combating violent and life-threatening forces that derived from violence itself. Individually, viewers see these characters in a new light, facing challenges that their more childlike versions wouldn’t have. It’s how the film injects the situation with enough realism to seem like a live-action horror film while still staying true to the animation.

Scooby-Doo on Zombie Island is akin to Scooby-Doo, Where Are you! going to college, spending countless nights partying, getting up early to class, and finally walking on that graduation stage with a diploma. It’s an evolution to the original show, willing to push on the horror the franchise is built on. It’s a shame this film seems to be the only achievement of that growth. Scooby-Doo on Zombie Island appears to be the rare shooting star in the entire franchise that has withstood the test of time.

KEEP READING: 'Scooby-Doo' Animated Prequel 'Velma,' Starring Mindy Kaling, Coming to HBO Max