'Ghost Adventures' Star -- Selling Haunted Las Vegas Lair ... Exorcism NOT Included

"Ghost Adventures" star Zak Bagans fled his Las Vegas home years ago -- but now he's finally ready to sell the place for dirt cheap ... with one demonic catch.

According to real estate sources ... Zak is unloading his 4,700-square-foot Vegas townhouse -- complete with a chrome toilet, hidden dungeon behind a bookcase, and alleged paranormal activity. All that for $459,000.

Zak tells TMZ he bought the pad for $370K, but claims he ended up with a real demon for a roommate after bringing home a human skull ... for work purposes.

He believes demonic forces yanked him outta bed and shoved his GF down a flight of stairs -- which might be the worst sales pitch ever. Instead of hiring an exorcist ... Zak says he got the hell out more than 2 years ago.