Test audiences thought the shocking ending of Sydney Sweeney's horror movie had to be seen to be believed. The director says they're wrong.

• The bloody ending of "Immaculate" is purposely ambiguous.
• Sydney Sweeney nailed the final scene, in which she gives birth,  on her first try.
• Here's how it was made, and how sound design kept the ending open to interpretation.

When Sydney Sweeney brought director Michael Mohan the script for "Immaculate," she told him she just wanted to be "covered in blood and go crazy."

Mohan was more than happy to deliver.