According to director Christopher Landon, Tree Gelbman's punchline, "Who takes their first date to Subway? It's not like you have a footlong," was improvised by Jessica Rothe.
The Bayfield University Baby killer costume was designed by Tony Gardner, who also designed the Ghostface mask, the horror icon of the Scream films, and which is a reworked version of the Father's Death Halloween costume.
The scene where Tree Gelbman walks through the campus quad naked had to be done quickly, given that it was being filmed on an active college campus, this presented the risk of students witnessing the scene being filmed and/or taking photos. The crew took extreme precautions to clear away any potential onlookers. In the end, they managed to do just 2-3 takes.
Director Christopher Landon tested wearing the option of a baby mask for the killer in the office and scared a worker, confirming his choice.
When asked why a baby mask: Christopher Landon says he needed a combination of something that would pass for a mascot on a college campus, that was both scary and funny at the same time, plus he was expecting a son at that time, so he had "baby on the brain."