History and specifics
Diad II orbited a single star and had a blue sky. It was situated along the galactic plane, providing a spectacle array of stars at night despite its lack of a moon. It had a warm climate ideally suited for the evolution of intelligent life. Plant life included purple and lemon-yellow colored trees. Blue-green tress grew ramrod straight for 70 feet with no branches except for a top canopy. Reeds grew along lake shores, and there were grasses and various colored flowers. Animal life included furry-bodied flying sailors and butterflies. Terrain included valleys, rolling hills and mountains. The planet had one large ocean.
In 2267, the starship USS Enterprise visited Diad II. James T. Kirk initially thought the world would make an ideal colonial prospect for the Federation, and allowed many of the crew to take shore leave. However, the dominant species, native butterflies, formed a group mind with a collective intelligence. As they lived dream lives, their stray thoughts overwhelmed ship's personnel with hallucinations of fulfilled fantasies, resulting in a temporary mutiny and at least one death. (TOS - The New Voyages short story: "The Winged Dreamers")
- one-horned deer