In "Stranger Things," Dustin's pet Mews is a cat.
Mews belongs to the Henderson family and appears during the second season, when Dustin secretly brings home a strange creature he names D'Artagnan, or Dart. Dustin initially believes Dart is a harmless, unusual tadpole-like animal from the Upside Down and tries to care for it in secret.
As Dart grows, his appetite and behavior become increasingly dangerous. He eventually escapes from his container and eats Mews. The incident forces Dustin to recognize that Dart is a juvenile Demogorgon, later commonly called a Demodog. Dustin hides the truth from his mother and claims that Mews may have wandered to another neighborhood.
Mews is sometimes confused with other animal references in the series, especially the Three Musketeers candy that Dustin uses to feed Dart. Dart's name also comes from D'Artagnan, a character in Alexandre Dumas's novel The Three Musketeers. The cat's fate is one of season two's darker consequences of Dustin's attempt to keep Dart as a pet.