Filmed entirely using Zoom during the COVID-19 lockdown.
(at around 36 mins) Although scripted the cast was allowed to improvise, for instance the moment when Haley sneezes and the cast reacts to it was not planned.
Based on a short film by director Rob Savage, where he pranked his friends during a zoom chat pretending to be attacked by something in his attic. He didn't inform his friends in order to get their genuine reactions to it. The video was released online and went viral. Savage then approached Shudder about making a feature length version.
Parts of the script were redacted so the cast didn't know what would happen throughout. Certain things were pre-recorded and played back for the cast to get their genuine reactions.
Every scene was shot on iPhones taped to the laptops.