An Enterprise security ensign attacked by the dikironium cloud creature on Argus X, who survives just long enough to confirm the sweet smell Kirk remembers from eleven years before.
Ensign Rizzo is a security officer in the second-season Original Series episode Obsession, played by Jerry Ayres.
During a survey of Argus X, Kirk catches a sickly sweet odour and sends Rizzo with two men to investigate. A gaseous cloud engulfs them. The other two die at once, drained of their red blood cells, while Rizzo is found barely alive and beamed up to sickbay.
Kirk insists on McCoy waking him for questioning. Rizzo manages to describe a smell like honey and a sense of something feeding on him, which convinces Kirk that this is the creature that killed half the crew of the USS Farragut. Rizzo dies soon afterwards. He was a friend of Ensign Garrovick, whose hesitation in the next attack echoes Kirk's own years earlier.