The comic that arguably has the most influence on The Penguin is Batman: Dark Victory by Jeph Loeb and Tim Sale, which serves as a direct sequel to Batman: The Long Halloween. In Batman: Dark Victory,

But one complete scene stood out to me in the finale as a deliberate set up for where we might see Oz in The Batman: Part 2. Almost as if Matt Reeves asked LeFranc to include this one sequence, just to lay the groundwork for a story he’d like to explore down the line.

The Penguin finale might have secretly introduced The Batman 2's villains. During the quick courtroom tete-a-tete between Oz (Colin Farrell) and Councilman Hady (Rhys Coiro), you may notice a peculiar print around the walls of the courtroom.