 The script for Scary Movie is actually a combination of two scripts  Dimension Films bought in 1998: "Last Summer I Screamed Because  Halloween Fell On Friday The 13th" written by the Wayans brothers  and Phil Beauman (qv); and "Scream If You Know What I Did Last  Halloween" by Jason Friedberg (qv) and Aaron Seltzer (I) (qv).  The latter was the working title for this project.