By the time that local haunted attraction impresario Brett Molitor acquired the Haunted Cave in 2013, it had largely abandoned its cave theme.
Molitor said modern haunted attractions need a strong narrative and must innovate within that narrative annually.
"When something hasn't changed for four years," he said, "customers know it."
Molitor said he took longtime Haunted Cave actors on several road trips to show them what cutting-edge Midwestern haunts were like.
Then they set about trying to come up with a new theme for the Cave. It took a little while.
"I had a guy come into my office with a big belly, wearing a pig mask and a red tutu," Molitor recalled, laughing. "And he said, 'What do you think?' And I said, 'Well, you're scary. I'll give you that.'"
Molitor and his charges eventually arrived at Hysterium, which features a haunted asylum theme with a similarly named fungus thrown in for good measure.
Patrons start in a waiting room that looks (and, better yet, smells) exactly like the foyer of a converted Victorian house owned by a small-town general practitioner.
They move on to a sewer room where it may take them a while to realize that live wires are touching the metal handrails they are using to keep them from plunging into the muck below.
What follows is a "warehouse" filled with rusty hazardous waste barrels, an old-timey pharmacy that probably won't have the cure for what ails you and a claustrophobia room in which the walls quite literally close in.
There are doors that lead to corridors of doors that, confusingly, lead to more corridors of doors.
At some point, you will encounter the startling Pumpkin King who stands 20 feet tall and looks like he might spend most of his days trying to eat Hobbits. There's also a mutated monkey and a demonic goat.
Hysterium's mutated monkey is roughly the size of any non-mutated monkey, but the demonic goat looks big enough to swallow a small grain silo.
Also, don't be surprised if you encounter something very much like a Titan from the horrific Japanese manga series, Attack on Titan.
A Titan is also big enough to swallow a small grain silo, but it's usually interested in softer and warmer fare.
Hysterium is packed with impressive details. There are full-sized skeletal horses with riders, old-fashioned carnival posters and a mortuary complete with one of those hook-laden meat conveyor systems that only adorn movie morgues.
Molitor is constantly on the lookout for striking accessories that he can add to his various haunts. He said the infernal horses and the Pumpkin King were purchased at an auction of items from a failed corn maze.
"They had eight semi loads of haunted house stuff," he said. "I was the only haunted house guy there. I got them for a song."
In recent years, Molitor - ever responsive to trends in the haunted attraction biz - has added four escape rooms to the Hysterium space.
These run year-round and operate independently of October haunt.
Escape rooms are themed, puzzle-filled adventures. Participants are locked in a room with a ticking timer and everything they need to escape. But it's never easy.
One of the Hysterium escape rooms unfolds like a classic mystery novel, two are devoted to international espionage and the last involves a serial killer.
The serial killer room, unlike the relatively genteel others, is "dark, scary, gruesome, a little crude, smelly, and a little gross," Molitor said.
One thing that makes the Hysterium escape rooms different from competitors in town, Molitor said, is that they're available for corporate functions.
Molitor has professional experience from General Motors with team building and facilitating team effectiveness. As it turns out, escape rooms are ideal for helping this process along. Who'd have thunk it?