The Saucer Kaiju, or Organic Saucers (円盤生物 Enban Sebutsu?), are living flying saucers or monsters who can turn into a saucer. Most of them appeared in Ultraman Leo. There they were summoned by Black Directive from Black Star, and many of them were some of the greatest foes Leo faced.
Saucer monsters appeared from episode forty onward, in the story arc "Terror of the Saucer Race Series".