Jay asks "what is it with alliteration and nicknames" referencing his nickname "The Crimson Comet," Barry's "The Scarlet Speedster," and countless other superheroes and supervillians in the comic books world.
After spending much of the episode trying to determine how many interdimensional portals exist, Dr. Stein and Cisco come up with an answer: 52. This is likely a nod to DC-52, the comic storylines on which the show (and much of this universe) is based.
Named after the first time Barry Allen and Jay Garrick meet in the comics.
First appearance of Patty Spivot, a love interest of Barry Allen's in the New 52 comics.
First appearance of Sand Demon; originally an enemy of Firestorm in the comics.