Warning: SPOILERS from Supergirl season 6, episode 1, "Rebirth".

Supergirl's season 6 premiere shares a trait with Smallville season 6's opener, as both episodes deal with the Phantom Zone. Like most Arrowverse shows, Supergirl never finished its fifth season due to the pandemic. Therefore, Supergirl's first episode back serves both as a season premiere and finale, to a certain extent. As Kara and her team went up against a super-powered Lex Luthor, they managed to take him down, but not without paying a price.

In the midst of their battle, Lex tries to use the Phantom Zone projector and ends up hitting Supergirl. While Alex manages to make Lex powerful, she is forced to watch her sister disappear in front of them. It will be up to Kara's team to try and get her out of the Phantom Zone, which is a corner of the DC Universe the Arrowverse hasn't explored. However, with Kara being stuck in the Phantom Zone, the Supergirl season 6 premiere gets a neat little parallel with The CW's original Superman-related series, Smallville. At the end of Smallville season 5, Lex became a vessel for General Zod, who sent Clark Kent to the Phantom Zone and set up his big challenge for the season 6 premiere.

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The Smallville version of the Phantom Zone is significantly different from Supergirl's interpretation. Unlike the Arrowverse variation, Jor-El was the one who created Smallville's take on the deadly dimensional prison. In the Arrowverse, the Phantom Zone isn't so much a separate dimension but rather a proper space where time doesn't pass or exist, to be more specific. That's why when Kara's pod broke out, she still looked 13 years old and hadn't aged a day since being sent away from Krypton. It's also worth noting that, like Smallville's Clark, Supergirl's Kara also got sent to the Phantom Zone by a Lex Luthor, even if he wasn't possessed by Zod.

Kara Sent to the phantom zone supergirl season 6

Little is known about Supergirl's incarnation of the Phantom Zone in more specifics. This arc will last for a few episodes, so Supergirl will get to explore this prison a bit more in-depth compared to Smallville. Most of the time, when Clark would get involved with his father's creation, it was mostly for the better part of an episode, which became a recurring thing in Smallville seasons 6, 8, and 10. In Arrowverse's case with Supergirl, at least they will let the viewers see the Phantom Zone for a number of episodes as the heroine tries to return back to Earth.

Since Supergirl's depiction of the Phantom Zone is visually different from Smallville's, it might mean they don't have the same way to escape it. Smallville established that a member of the House of El could use their blood to open Jor-El's secret gateway. Although, Zor-El in the Smallville universe built his own secret escape portal inside a cave that Laura Vandervoort's Supergirl discovered when she was trapped. While obviously not connected to one another, it's still a fun coincidence that Supergirl's season 6 premiere ended with Kara Zor-El getting trapped while the start of Smallville season 6 saw Clark Kent escaping the Phantom Zone.

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