What's your favorite "so-bad-it's-good" movie?

I love Xanadu (released in 1980; stars Olivia Newton-John and Gene Kelley...go watch it!!!!) and Purple Rain (Prince!!!!) as well as Grey Gardens (the original documentary and the 2009 remake lmfao). But these aren't like...good movies. They're awful! And great! Other honorable (horrible) mentions are all the 90s Batman movies. How about you?