The Talosian singing plant was a plant native to Talos IV. It was a blue plant with a single, broad lilypad-shaped leaf on a long stem. It could be found growing among the many boulders and plains that made up the planet's surface.
As its structure vibrated in the near constant winds on the planet's surface, the Talosian singing plant emitted a beautiful, wailing chime, which was very pleasing to the ear. Holding the plant's leaf still in one's hands would cause the song to cease, but it would resume again once let go. Even Vulcans were not immune to finding pleasure in the sound, as evidenced by Spock's joyous reaction. (TOS: "The Cage", "The Menagerie, Part I")