Something is going horribly, astoundingly wrong at the home of Mr. and Mrs. Claus.

Gingerbread men rampage through the kitchen, leaving a bloody mess. The television blips in and out while “Rudolph the Red Nose Reindeer” plays on the screen. Demonic elves decorate Christmas trees with skulls.

But it’s all in the name of horror and fun at 13th Floor’s Krampus haunted house.

The 13th Floor has become a Denver institution during October with people waiting in long lines to get spooked, but the demand for scary fun is expanding in the city and across the United States as Halloween grows in popularity.

“People in general are looking for Halloween year-round,” said Samantha Beranek, a 13th Floor spokeswoman. “That’s what we’ve been seeing.”

Ryan McLellan, the 13th Floor’s production manager, said the Krampus craze is a result of the movie franchise as well as the growing Halloween industry. In 2024, the National Retail Federation predicted Americans would spend $11.6 billion on costumes, candies and decorations at Halloween. That’s up from $8.8 billion just five years ago.

This year, people in Denver can also meet Krampus at pop-up bars, Christmas markets and even a burlesque show; TRVE Brewing also hosts an annual Krampusnacht on Dec. 14.

“It’s a mashup of Halloween and Christmas,” McLellan said. “Those are people’s two favorite holidays.”

The 13th Floor’s Krampus haunt is in its eighth year, and it returns for a three-night run on Dec. 13. Yes, that’s a Friday. Bring on the scares.

“Krampus alone is pretty scary but you might see Santa Claus in a form that you’ve never seen,” McLellan explained. “It presents traditional characters in a new way. It’s a little darker and scary.”

Krampus originated in Germany and Austria where folklore and legends told of a half-goat, half-demon creature who would spank bad children during Winter Solstice celebrations. Good children would be treated to presents by St. Nick.

The Krampus character was relatively obscure in the United States until the 2015 holiday horror-comedy movie, “Krampus” was released.

That’s when Krampus-themed haunts took off, said McLellan, who has worked in the haunted house industry since he was a teen.

For the Krampus haunt, the 13th Floor sticks with many of the sets and props visitors see at Halloween. But the path through the “winter horrorland” involves Christmas lights, tinsel and winter monsters. Actors dressed as elves, snowmen, the Grinch and, of course, Krampus, will provide the scares.

The year’s theme is Krampus: The Fright Before Christmas, and the scene takes visitors to the home of Santa and Mrs. Claus. They first see the home from the outside with Santa slowly rocking in a chair on the front porch while growls and screams echo from inside.

“Parts of me think it’s even scarier than Halloween,” McLellan said.

Lo Olguin, who manages the 13th Floor’s costume department, will pull on one of the scary masks to stalk customers as they wait in line for the Krampus haunt. He said those people are the same thrill-seekers who come at Halloween.

“It’s something that’s starting to be more popular,” Olguin said. “We’ve already got a tradition so we’re running with it. We fell right in line.”

Where to see Krampus in Denver?

• The 13th Floor’s Krampus: The Fright Before Christmas runs from 7 to 10 p.m., Dec. 13-15 at 3400 E. 52nd Ave. Tickets start at $29.99 but can be upgraded to skip the line, visit secret bars or add other attractions, such as a mini escape room or axe throwing. The 13th Floor also hosts a toy drive; donate when you buy tickets or drop off a toy on-site. 13thfloorhauntedhouse.com/krampus.

• TRVE Brewing’s Krampusnacht runs from 5 to 10 p.m. on Saturday, Dec. 14, at Import Mechanics (two doors down from the brewery) at 235 Broadway. In addition to a beer release, there will be Krampus sweaters for purchase, whiskey from Laws Whiskey House and cocktails from The Crypt. Take a pic with Krampus himself or peruse the Krampusmarkt.

• The Krampus Room at The Electric Cure. This 21 and up cocktail bar is open from 3 to 11:50 p.m., through Dec. 31 at 5350 W. 25th Ave, Edgewater. Visit https://www.theelectriccure.com/event-details/the-krampus-room-holiday-bar.

• Krampus Cove is an immersive cocktail experience at the Emerald Eye on Larimer Square through Dec. 31, 1403 Larimer St.

Sit for an instant photo with Krampus at Ritual Craft, 7700 W. 44th Ave., Wheat Ridge. Photos are walk-in only from noon to 9 p.m., on Dec. 14. The first picture costs $10 with additional copies costing $5 — four people maximum per photo. Krampus will take a break between 3 and 4 p.m. www.ritualcravt.com/product/polaroids-with-krampus-december-14th-2024/.