Some kids go to an old Haunted House attraction to learn about Fear and participate in a study. Once there, some crazy killer starts taking them out.
Party house is actually portal to evil dimension, and horde of murderous beings slaughter partygoers, then homicidal children attack cars, before evildoers are all pulled back through the portal to invade another dimension.
A gang leader attempts to bring fallen comrades back from the dead, resulting in vampires overrunning a city.
