Instead of rewriting the whole movie, good spoof writers insert explicit scenes between original scenes. For example:
The author takes the skeleton of a famous film’s storyline but replaces the romantic/emotional tension with graphic sexual encounters.
During the late 20th century, these novels were often the target of moral policing. The association with cinema made them more visible. While mainstream cinema was celebrated, these "spoof" novels were viewed as "parippuvada" (cheap/populist) culture.
The most successful spoof Kambi novels don’t just borrow characters; they borrow screenplay structure.