The post-credits scene of “The Batman” contains a message from the Riddler saying “Goodbye,” along with the URL to his website shown in the film. While the film itself contains Easter eggs and references to iconic villains, Riddler’s website contains perhaps the most intriguing one.
If one accesses the website (www.rataalada.com), they will be greeted with three riddles, and solving them will lead to a password-protected .zip file. The file contains old footage from Thomas Wayne’s mayoral campaign, with the words “Hush!” written over the footage at one point.
Hush refers to Thomas Elliot, the identity-thieving villain from" Batman: Hush," who was originally a childhood friend of Bruce Wayne. Hush was also hinted at in the film itself, as Thomas Wayne asks Falcone to silence an inquisitive reporter, whose last name turns out to be Elliot.
In the original “Batman: Hush,” it turns out that Elliot had been working with the Riddler the whole time. Given how the character has been subtly hinted at in the film and the website Easter egg, fans can probably expect to see him in a later film.