 What was on exhibit in the Groacian parade?
"You've been here on Groac for four years, Miss Meuhl. The pale-featured Groacian vibrated his throat-bladder in a distressed bleat. An elaborate one picked out in pinkish paint seemed to indicate the Groacian equivalent of a bar. A Groacian bartender was dispensing clay pots of alcoholic drink from the bar-pit at the center of the room. A tall Groacian vibrated his mandibles in a gesture of contempt. Retief backed, rounded a corner into a narrow alley-like passage, deserted, silent ... except for the following Groacian. Two Groaci wearing heavy eye-shields and elaborate crest ornaments indicative of rank rose as Retief entered the room. "One hour ago," The Groacian said, "a Groacian national was brought to hospital suffering from serious contusions.
 people they had taken as prisoners
 Groacian government officials  people they had taken as prisoners  animals from all over the galaxy  people visiting from Earth