Korriklimm was a Thetran inventor. He created a series of robots to serve vacationers on the holiday planet of Nestra, which was run by the Thetrans. The robots had the ability to learn from their experiences, but they could not extrapolate beyond those experiences. As a result, the robot Lakksis would only give vacationers what they enjoyed, and when they became sick, sent them to the infirmary. However, he would not give them medicine or treatment, because those things were not enjoyable.
Korriklimm became one of the missing when Lakksis placed him in the infirmary. Korriklimm's partner asked the Sixth Doctor to look for him. The Doctor found him in the infirmary, suffering from diabetes. Korriklimm received the treatment he needed. (PROSE: Wish You Were Here)