The Saucer Beasts, 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 the Black Star, and many of them were some of the greatest foes Leo faced.
A set of twelve Saucer Beasts appeared from episode forty onward, in the story arc "Terror of the Saucer Race Series".
In addition, a thirteenth Saucer Beast, Roberuga, debuted in Ultraman Mebius. Though not part of the original set, Roberuga was formed from the wreckage of Black Star in the years following its destruction by Leo, thus making the monster the latest generation of Saucer Beast, though its formation was by chance.