Filmed entirely using Zoom during the COVID-19 lockdown.
(at around 36 mins) Although given scripts, the cast were allowed to improvise, and often had to. For instance, Haley's sneeze and the others' reaction to it were not planned.
Based on a short film by director Rob Savage, in which 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.