Dr. Richard Moriarty, the retired pediatrician who created the popular mascot of the Pittsburgh Poison Center, Mr. Yuk has died at the age of 83.

Moriarty was raised in the Lawrenceville neighborhood and obtained his bachelor’s and medical degrees from the University of Pittsburgh. He was involved in the founding of the Pittsburgh Poison Center at the Children’s Hospital of Pittsburgh and served as its director.

Moriarty developed a poison prevention education program aimed at children that spawned Mr. Yuk in 1971. Some have declared Mr. Yuk to be the world’s first emoji.

“Dr. Moriarty was instrumental in the development and promotion of Mr. Yuk, a Pittsburgh icon that serves as a poison prevention symbol and promotes poison center awareness. Dr. Moriarty’s passion for Mr. Yuk and poison prevention was unmatched. We will work hard to continue Dr. Moriarty’s mission through ongoing promotion of Mr. Yuk in our communities,” the Pittsburgh Poison Center said in a statement.

Moriarty worked as an associate professor at the University of Pittsburgh School of Medicine from 1977 to 2004. He served on the boards of the Carnegie Museum of Natural History and Pittsburgh Public Theater.

Moriarty was an intensive care patient for three weeks up until his death. He underwent mitral valve replacement surgery three months ago.

He is survived by his husband and several nieces and nephews.