Well, the all-time acknowledged Bad Movie is "Plan Nine from Outer Space" by the inimitable Ed Wood, Jr. But my favorite Bad Movie is "The Conqueror" with John Wayne and Susan Hayward (1956). Imagine: The Duke as Genghis Khan, eyebrows tweezed, Oriential Bishop's miter on his head, but still, leeringly, The Duke.
In an unforgettable scene, the Duke and his hordes (buzzing with flies and dripping yak fat) have ambushed a Tatar caravan and captured Bortai (Hayward), the daughter of Kumlek, leader of the Tatars. Hayward, doing her best imitation of an outraged noblewoman (and trying to keep a straight face) sneers, "...and how does the leader of the MON-gols [practically spitting that word] intend to keep a daughter of KUM-lek in the style she is accustomed to?" Without missing a beat, The Duke replies, leeringly, "By day, the pelts of my sheep shall keep thee warm...and by night, the heat of my body shall protect thee from the des-urt winds..." I fell right off my seat laughing when I saw that scene in 1956.