17. Disaster Movie (2008)
Though the films of Jason Friedberg and Aaron Seltzer (Epic Movie, Meet the Spartans) have been almost universally panned by critics, they've generally performed well enough at the box office and typically achieved generous, baffling CinemaScores in the C+ to C- range.
Disaster Movie, then, is the outlier: the low-effort parody movie that seemingly broke audience's resolve. Releasing the very same year as Meet the Spartans, Disaster Movie's F rating and lukewarm box office apparently proved that, yes, there is such a thing as stupidity saturation, even for the audiences who religiously flock to these movies.
It probably didn't help that Kim Kardashian made her (awful) acting debut and the film parodied movies that the target audience almost certainly hadn't seen (namely No Country for Old Men and Juno).
Crista Flanagan gets a few smiles for her spot-on Juno impression, but otherwise this is a virtually laughless slog, even at a mere 87 minutes.