Continuity mistake: When the scientist's face starts to melt, the stuff on the wall keeps changing all the time.
Visible crew/equipment: Near the end of the film, when she lands behind the stairs. If you look in the right hand corner, underneath the stairs, you can see tennis shoes running by.
Visible crew/equipment: When Diane and Steve go to their neighbor's house after the scene of the chair sliding across the floor, there's a flash of lightning that reveals a shadow of a fan that's blowing on the actors on the left side of the house.
Answer: Ectoplasm.
Phixius ★