Dustin Henderson’s pet demogorgon in Stranger Things season 2 is called D’Artagnan.
Dustin finds the small creature and initially believes it may be an unusual animal. He gives it the nickname Dart, short for D’Artagnan, after keeping it hidden and feeding it. The creature later grows into a dangerous juvenile demogorgon, part of the species the group commonly calls demodogs.
D’Artagnan’s storyline shows how the creatures connected to the Upside Down can appear vulnerable or harmless before developing into major threats. Dustin’s attachment to Dart also creates conflict with his friends, who recognize the danger sooner than he does.
The name is a reference to D’Artagnan, one of the central characters in Alexandre Dumas’s novel The Three Musketeers. “Dart” is the familiar name used in the show, but D’Artagnan is the creature’s fuller given name.