A member of the Enterprise crew who joined the second landing party to planet M-113 in 2266 and became one of the salt creature's victims near the archaeological ruins.
Sturgeon is an Enterprise crewman in the episode The Man Trap. After Darnell dies in unexplained circumstances on M-113, Kirk returns to the planet with McCoy and two crewmen, Sturgeon and Green, to press Professor Robert Crater for answers.
The two men are left to look around the ruins while the officers argue with Crater. Kirk and McCoy soon find Sturgeon lying dead, his face covered in the same red, ring-shaped mottling seen on Darnell and his body stripped of salt.
His death, and the discovery that Green is missing, convince Kirk that something on the planet is killing his people. The crewman's name is generally taken as a nod to the science fiction author Theodore Sturgeon, who wrote for the series.