Yorick was made of papier maché, with a tube in his mouth that allowed him to swallow things. He was a precursor to hungry monsters like Cookie Monster. Through the years, Jim Henson experimented with his voice; either making grunting noises, talking in a really gruff voice, or remaining silent.
In one classic variety show sketch, Kermit wore a blonde wig and lip-synched "I've Grown Accustomed to Your Face" to Yorick, as the hungry monster tried to eat Kermit's foot. The sketch was performed on many different shows, including The Ed Sullivan Show in February, 1967.
In a survey done in Washington, D.C. during the Sam and Friends run, Yorick was voted the most popular character on the show. The Evening Star reported: "The contest to decide the most popular muppet (sic) in which 6,000 votes were cast by mail moved Sam into second place behind Yorick. Mushmellon came in third, followed closely byKermit."
A recostumed Yorick appeared as the Palace Guard inTales of the Tinkerdee. Yorick made one comeback appearance in The Muppets: A Celebration of 30 Years in which Kermit asks Sam and Harry the Hipster where Yorick is only to find he's right next to him (eating through a cloth with a face drawn on it, echoing the gag from "I've Grown Accustomed to Your Face"). Likewise for old time's sake, he tries to devour Kermit's hand.