Mr. Yuk was the icon of an effective anti-poisoning campaign aimed at young children that was developed by the Children’s Hospital of Pittsburgh. The Children’s Hospital opened the country’s first poison center in 1971 and also set up the first 24-hour poison hotline. The hospital helped spread this concept to other places, too, by producing generic TV commercials that could be customized with local telephone numbers and lurid, lime green Mr. Yuk stickers.

In 1971, there was really no such thing as today’s child safe packaging, and the hospital’s director, Dr. Richard Moriarty, saw a problem with the traditional “skull and crossbones” poison warning: As a resident of Pittsburgh and a fan of the Pittsburgh Pirates baseball team, Moriarty saw how local children might come to think of this symbol as something to do with the Pirates—or pirates—and that it might indicate “fun” to them, and came up with the concept of Mr. Yuk to replace it.

If you grew up in the greater Pittsburgh area, for generations the Mr. Yuk song was drilled into your head, but it was well-known in other parts of the country, too. My mother had a half-used sheet of Mr Yuk stickers in a drawer in her kitchen for decades. It might still be there for all I know. The Children’s Hospital of Pittsburgh has on online gift shop where you can purchase Mr Yuk stickers and more.

Dig the spooky Moog soundtrack and paranoiac visions of demonically possessed common household cleansers in the infamous Mr. Yuk TV spot. Note how the local branding is badly botched: