Even during the best scary movies, the audience still remains seated. Halloween is the only time of year when they get to engage in the action, with haunted houses that let patrons step into a scene and become a part of the story, if they dare.

The best haunted houses in Milwaukee have designed disturbing performances that are not only creative but genuinely creepy — and definitely not recommended for the easily spooked. If you like all things scary but can’t make it to every haunted spot in the area this Halloween season, these are two places you shouldn’t miss.

Mars Haunted House

If it weren’t for the deranged clowns stalking passersby outside the house’s entrance, it would be easy to pass the Mars Haunted House and not realize that it is a haunted attraction.

“Normally you think a haunted house would be in a dark wooded area,” said Ryan Burk, a junior in the College of Communication. “But (Mars Haunted House) was just as scary because of the story behind it.”

As the story goes, the building was constructed in the 1880s to serve as space for retail shops. Eventually, it was converted into apartment buildings and doctors’ offices. The Milton family lived in one of the apartments, and the father, Jacob Milton, tragically shot his family as well as himself on Oct. 3, 1943 after losing his job.

After the murders, other apartment tenants gradually vacated the building, after reporting that furniture would appear in different places without anyone admitting to moving it.

The complex was supposed to be renovated and made into new apartments. But, according to the Mars website, when experienced construction workers began to get hurt on the job and their new renovations were inexplicably destroyed, work stopped. The space was converted into Mars Haunted House in 1993.

During construction on the haunted house, everything seemed to mysteriously shut down in the same particular corner after 11 p.m. Electricity and power tools stopped working, and the corner became suddenly cold.

John Klein, owner and manager of the building, hired a team of paranormal specialists to observe potential paranormal activities.

“I was really skeptical about it at first,” Klein said. “I’m not a big believer about stuff like this — until I was able to sit with this group.”

Klein said he didn’t tell the medium anything about the space; he wanted to see what she would come up with on her own.

“She said she felt something piercing her in her spine,” Klein said. “(She said) someone was murdered in that particular corner and they were still living there.”

While the Mars Haunted House was originally based on dark mazes and creepy noises, it now draws inspiration from the historical events of the structure, turning them into scenes for the haunted attraction.

“Whether it is paranormal activity or not, it is still creepy being in the presence of confirmed murder,” Burk said.

Mars Haunted House, 734 W. Mitchell St., is open from 7 to 11:30 p.m. on Fridays and Saturdays and 7 to 10 p.m. on Sundays in October. Mars is also open from 7 to 10 p.m. on Thursday, Oct. 27 and Monday, Oct. 31. Admission is $12. For more info, visit Marshauntedhouse.com.

Wisconsin Fear Grounds

Ann Marie Gavinksi used to decorate her home with elaborate Halloween decorations. The decorations took two weeks to put up and one week to take down. After a reporter told Gavinksi the decorations were better than some commercial productions, she and her husband decided to open a haunted house in 2004.

Now, Gavinski operates three haunted houses collectively ranked as the number one haunted house in America by Haunted Attraction Magazine. They are a package deal, but each house tells a separate story.

This year, the story centers on Morgan Le Fay, an infamous witch from Arthurian legend. The three houses of the Fear Grounds each depict a different setting in her world.

House number one, “Morgan Manor,” is Morgan’s home. The Victorian-style building is the most traditional haunted house, with a den, nursery, courtyards and parlors.

“Morgan’s Torment” is a separate house, but is depicted as the basement of “Morgan Manor.” Morgan and other witches cast spells and make potions in the basement. The third haunted house, “Unstable,” takes place in Morgan’s stables, where the animals are served for dinner.

“We want you to feel a lot of highs and lows, like a roller coaster,” Gavinksi said. “We want to get people to jump out at you, gross you out, creep you out and bring in humor. It is a highly choreographed show.”

A haunted house truly is a theater production. About 70 percent of Gavinski’s houses are renovated from last year with new sets, scripts and ideas. The 2012 show is already in the making.

“We’re reinventing ourselves every year,” Gavinski said.

Wisconsin Fear Grounds, 1000 Northview Rd., Waukesha, is open 6:45 to 11:30 p.m. on Fridays and Saturdays in October. It is also open 6:45 to 10 p.m. on October 26, 27, 30 and 31 (show a student ID on these nights for a free gift). Admission prices range from $13 to $45, depending on number of houses you attend. For more info and online specials, visit Wisconsinfeargrounds.com.