From Nookipedia, the Animal Crossing wiki
Frillard (きょしょー, Kyoshō), also known as Master Fillard, is a special character in Animal Crossing: City Folk. He makes his appearances in the Marquee taking Dr. Shrunk's place on rare occasions. He is deep-voiced, like cranky villagers.
Frillard is based on a frilled lizard. He is a yellow lizard with gold spots around him. He has thick, white eyebrows and seems to be old; in one of his performances, he says 110 is young. He also uses a cane and has purple clothing. His name derives from his being a frill-necked lizard.
There is no way to know when Master Frillard will perform next. Only by talking to The Marquee clerk and choosing one of these emotions, if they are available at the time.
Frillard and Dr. Shrunk
Animals at the city depicts him a a great entertainer with his humorous jokes. Villagers also say Dr. Shrunk is Master Frillard's student. He teaches six different emotions unknown to Dr. Shrunk. They are as follows:
Though he does not appear in Animal Crossing: New Leaf, Dr. Shrunk will refer to the jokes that correspond to those emotions as belonging to his master.
Frillard appears as a spectator in the Town and City stage and as a trophy.