Scary Movie 4 is mainly a parody of several early‑2000s horror and sci‑fi hits, not just one single movie.

Main movies it parodies

  • The Grudge (ghost boy, cursed house setup).
  • War of the Worlds (alien “tripod” invasion and overall disaster plot).
  • The Village (creepy village and “creatures in the woods” elements).
  • The Saw franchise (the opening trap scene with Shaq and Dr. Phil).

Other films heavily spoofed

  • Million Dollar Baby – especially in the boxing/parody hospital scenes.
  • Brokeback Mountain – in the tent scene gag.
  • Hustle & Flow and a few other pop‑culture references get shorter spoof moments.

In one line:
Scary Movie 4 is a comedy mash‑up parodying The Grudge, War of the Worlds, The Village, the Saw movies, plus bits of Million Dollar Baby, Brokeback Mountain, and a few other 2000s hits.

TL;DR: If you’re wondering “what is Scary Movie 4 a parody of” , it mainly spoofs The Grudge, War of the Worlds, The Village, and Saw, while also mocking Million Dollar Baby and Brokeback Mountain.

Information gathered from public forums or data available on the internet and portrayed here.