The Houses October Built (2014) online

Beneath the fake blood and cheap masks of countless haunted house attractions across the country, there are whispers of truly terrifying alternatives. Looking to find an authentic, blood-curdling good fright for Halloween, five friends set off on a road trip in an RV to track down these underground Haunts. Just when their search seems to reach a dead end, strange and disturbing things start happening and it becomes clear that the Haunt has come to them...