The opening quote and loose plot come from the fairytale "The Two Brothers".
As Nick starts to follow Ariel from the club, there is a mural of a fire-breathing dragon on the wall across the street.
Ariel is played by Danielle Panabaker. She stars in the show The Flash. In Grimm she's a fire breathing dragon type wesen. On The Flash, she plays Caitlin who, after Flashpoint, develops ice powers.
The title derives from Quetzalcoatl, a Mesoamerican deity whose name comes from the Nahuatl language and means "feathered serpent."
The song playing at the club during Ariel's performance is "This Fire" by Franz Ferdinand.