He used to buy props, but now they make them, Krohn said.
One of the highlights is the alien spaceship that is 13 feet high and 12 feet long — it's just a facade.
They took pictures last year of the people coming out of the attraction, Krohn said.
"Ninety percent of them walked out with a smile on their face even though they were screaming inside," he said. "We don't hurt them — just scare 'em. One lady ran through a plastic wall. We had to shut down and get the stapler gun to pull the wall back up."
Helping Krohn are his friends, La Crescenta natives Steve and Gary Trousdale.
Gary Trousdale started creating haunted houses 23 years ago at his home in Northridge. When he moved, Krohn volunteered his property for the event.
Steve Trousdale is an engineer and helps to put things together safely, he said. His brother is a director of animation, having worked for Walt Disney Co. and DreamWorks.
"He can see a picture in his mind of what he wants, and we draw it out and make it happen," Steve Trousdale said. "David is a real estate agent and also a great craftsman. He makes furniture. He comes into play making the pneumatic (air-powered) gags."
The attraction is free to the public, he added.
"We never charge and we never will. We have thousands of dollars invested, and we don't charge because it wouldn't be fun anymore. We do it to scare people and to have fun."
The other two people involved are Alan Bernhoft, who does the soundtrack and teasers on YouTube, and Jeff Sellers, who helps with construction. He joined the group this year.
This year's storyline is that a group of trailer-dwelling folk see an alien spacecraft crash land into a cemetery, and havoc ensues, Steve Trousdale said.
The spacecraft will look like it's on fire, and there will be a news van with a continuous loop with the fake reports of the scene of the crash.
"That will keep people occupied who are waiting in line to go through the house," Steve Trousdale said. "I will be calling out instructions from a land cruiser painted in camouflage design with a machine gun shooting blanks."
The last room will be the scariest, he added.
"People will turn around and try to leave in the opposite direction," he said. "We've had people run straight through the walls, and I think this year might be worse."