'Supergirl': How "Bunker Hill" Sets Up "Elseworlds"

Tonight's episode of Supergirl gave viewers a lot to think about as The CW series head into its [...]

Tonight's episode of Supergirl gave viewers a lot to think about as The CW series head into its winter hiatus -- but not before setting things up for "Elseworlds" in a shocking closing scene.

Spoiler's for tonight's episode of Supergirl, "Bunker Hill", below.

Tonight's Supergirl closed with Agent Liberty unmasked and behind bars while Supergirl found herself out at the DEO rather than reveal her own secret identity. While that's a lot to process as it is, it's the scene that came next that opened the doors wide open for the Arrowverse crossover kicking off next week, "Elseworlds". You can check out the scene in the video above.

The scene takes place on a never-before-heard of world, Earth-90 and to say Earth-90 has seen better days would be an understatement. The scorched and devastated earth is littered with the bodies of heroes -- many of the very familiar to DC Comics fans. Glimpses of Stargirl, The Ray, and even a helmet for one of the Hawks among many others can be seen strewn about on this devastated world. The only sign of life is that of the Flash, but Earth-90 Flash isn't Grant Gustin's Barry Allen. Instead, it's John Wesley Shipp in his iconic red speedster suit from the 1990's The Flash series.

And if that reveal wasn't enough, it's what comes next that was truly chilling. Flash drags himself towards what is revealed to be The Monitor (LaMonica Garrett). Flash asks The Monitor what he's done to which the Monitor replies that they did it to themselves and now they are going to perish. He opens a large book he's holding, and energy begins to flow from it -- and Flash takes off running, the lightning bolt emblem on his chest the last thing we see before the screen goes black.

While we've known for a while that Shipp would be making an appearance in "Elseworlds" while clad in his 90s Flash suit, this scene seems to confirm that the crossover ties the 1990's CBS series to the Arrowverse in some fashion -- even if only "spiritually". It also opens up quite a few more questions about what The Monitor's role in "Elseworlds" will be and what, exactly, the heroes are facing in the three-night crossover event.

"LaMonica was ridiculous, like seeing him in his suit, he's just a monster," The Flash star Grant Gustin said of Garrett's performance. "He's like an absolute unit. He doesn't have to do a lot with his performance. He's so intimidating with just these subtleties, so that's dope."

You can check out the official synopsis for each night of the "Elseworlds" crossover here as well as check out our listing of every character confirmed for the event here.

What did you think about the surprise lead in to "Elseworlds" tonight? Let us know your thoughts in the comments.

The Arrowverse crossover event, "Elseworlds", will begin on with The Flash in a temporary time slot on Sunday, December 9th and continue with Arrow on Monday, December 10th before concluding with Supergirl Tuesday, December 11th.