Gary stating they "dare to defy" is a reference to the CW's slogan.
In the original Hellblazer comics, Constantine and his band Mucous Membrane performed during the original wave of punk music featured here during the 70s, and the comics were written and set starting in the 80s. Because the TV Constantine cannot be from that era, his band is meant to be from later and he is just a fan of this era, but this episode is partially a nod to his real history.
The episode's title is a reference to the ABBA song of the same name; Ray even mutters "Mama Mia" as an exclamation instead of the standard cursing.
Mona was originally named Alaska Yu.
The second episode to show a saber-tooth cat, first time was the previous season episode Freakshow (2017).