A Delta Quadrant people whose few survivors of a planetary catastrophe entered linked stasis, only to be held hostage by the Clown, a manifestation of their own fear.
The Kohl are a humanoid species seen in the Voyager episode The Thaw. Nineteen years before Voyager's arrival, a major solar flare ruined their world, and a handful of people from the Kohl settlement went into hibernation with their minds joined in a computer-generated environment meant to keep them occupied.
The system, which reads their thoughts, gave shape to their dread as a grinning Clown surrounded by carnival figures. He cannot survive if they wake, so he keeps them prisoner, and two have already died of fright at his hands. Harry Kim and Torres enter the link and Kim is caught as well.
The Doctor, being immune, serves as negotiator. Janeway finally offers herself in exchange for the hostages, but sends only a projection, and the Clown fades away as the sleepers are revived.