Venom: The Last Dance’s opening follows Eddie Brock’s story after Spider-Man: No Way Home. However, the film changes a few elements from what viewers saw in No Way Home’s post-credits scene. Here’s how Venom: The Last Dance retcons the Symbiote’s previous appearance.
Venom: The Last Dance opening retcons how Eddie returns to the SSU
In the post-credits scene for Venom: Let There Be Carnage, Venom and Eddie get taken to the MCU’s Earth-616 thanks to Doctor Strange’s botched spell in Spider-Man: No Way Home. But as Doctor Strange tried to make everyone forget about Peter Parker in No Way Home, Eddie and Venom got sent back to their original Earth-688, which is the home of Sony’s Spider-Man Universe (SSU).
Venom: The Last Dance begins right where Spider-Man: No Way Home ended. However, it changes how Eddie gets pulled back to Earth-688. In No Way Home, Eddie got sent back to the SSU with a glowing white effect. It was similar to how others, including Electro, Green Goblin, Doc Ock, the Lizard, Sandman, and the two Spider-Men, were sent back. Even Morbius stayed consistent with this glowing effect while pulling Adrian Toomes / the Vulture from the MCU to the SSU.
But in Venom: The Last Dance’s opening, Eddie and Venom get pulled into the SSU through a yellow portal. This portal is similar to the ones that Knull opens for his Xenophages later in the film. This raises the question of whether Knull was involved in pulling Eddie and Venom back. However, this doesn’t seem likely given the plot of the film. If Knull could do that, he’d simply pull Eddie and Venom onto Klyntar to obtain the Codex.
So it seems most likely that Eddie was sent back because of Doctor Strange’s spell. Sony only appears to have retconned how he gets transported.
Additionally, a sliver of Venom goo was originally left at the bar counter on MCU’s Earth-616. But now, Venom leaves a piece of him in the SSU’s bar instead, which later gets collected by Rex Strickland. Whether this was also meant to be a retcon, or whether Venom left pieces of himself in both the MCU and the SSU, remains to be seen.
