Their first appearance was a scene at Birdland in season 21, where they sang a song about fur. In a subsequent season, they performed "Brush Boogie." In Episode 2749, one of them appears to sing "Sound It Out" to a clarinet player named Dan, who is learning to read.
Their name is a reference to the 1960s pop girl group The Shangri-Las.
- All three singers' voices are dubbed. Ivy Austin performed one of them.
- The Shagri-Las are among the very few monsters with visible ears.
- All three puppets later appeared with different features as members of Rosita's family. One was used frequently as an AM monster.
- Their design is very similar to Mel, though Mel possesses horns, a chubbier body and a thinner face.