Triangularis natives are members of an advanced unnamed civilization on Triangularis III. They were noted for their vanity, having developed a vanity transporter technology used just to alter their appearance.
History
In 2267 or 2268, James T. Kirk beamed down to visit the natives of Triangularis III when the Federation starship USS Enterprise orbited the planet. (TOS - New Visions comic: "Made Out of Mudd")