Cratniks were a species of sentient insectoids. With their bulging eyes and extendible mandibles, their appearance was considered repulsive by Human standards. The staple food of the Cratniks was a species of small, furry mammals, which they preferred to eat live. Visitors were frequently offered these small mammals as a sign of hospitality. While Cratniks could become violently angry if such an offer was impolitely refused, they would accept a polite refusal from non-Cratniks who were vegetarians or who would not eat raw food.