6 Highlights from Part 1 of CW 'Elseworlds' Crossover Event as Green Arrow and The Flash Swap Bodies

The latest DCW Universe crossover event kicked off in fine fashion Sunday night with a special episode of "The Flash," taking over the timeslot usually held by "Supergirl."

The swap proved necessary as this story starts with a bizarre body swap between Green Arrow and The Flash, with Supergirl not factoring into the story until quite a while later. Not to worry, though, as she'll be wrapping up this three-part crossover on Tuesday night.

Things started off pretty ambitiously, too, with the mysterious Monitor setting in motion a series of events that could well prove the end of Earth-1, and all of this after apparently having a hand in the destruction of Earth-90. What's that? Not familiar with that Earth?

Well, long-time DC fans certainly are, as it's a callback to a certain television show from almost 30 years ago. And that was just one of many callbacks and shout-outs to DC television and movies through the years in this first part of the three-part event.

Check out our six favorite highlights from Part 1 below:

We already knew it was coming, but it turned out even more delightful in execution. Oliver and Barry's body swap was the gift that just kept on giving throughout the episode, and it looks like this fun is set to continue as the crossover event heads into "Arrow" Monday night before wrapping up in "Supergirl" on Tuesday.

The best part came when Barry and Oliver realized that they needed to adopt one another's demeanor as well in order to fully tap into their body-swapped powers. That means we got to see Stephen Amell try to be cheery and happy while Grant Gustin channeled dark and brooding. Neither quite fit, but it sure was fun watching them try.

Barry pointlessly telling Amazo "You have failed this city!" before blasting him with an arrow was easily one of the funniest moments of the night.

Admit it, you were stoked for the "Smallville" shout-out, but while we all kind of knew the Kent family farm from the long-running WB/CW series was going to be featured, nobody prepared us for that rocking theme song to accompany it. It almost overshadowed the introduction of Lois Lane (Elizabeth Tulloch) to the mythos.

But mostly it made us really, really, really want a Superman series. It's been a while now, and Tyler Hoechlin has really made the role his own. Plus, now that you've given him a familiar farm and a firecracker of a girlfriend, who knows his secret identity, we're ready to explore a new television chapter in the caped crusader's life.

Besides, the DC Extended Universe of films is kind of a mess right now. Who knows if we'll ever get another Superman on the big screen, and even if we do, who cares. Just call it another parallel earth and we're good to go. These glimpses into Superman's world only make us want to go on these journeys with him and Lois.

We got "Smallville" vibes from the set, but Hoechlin and Tulloch were totally giving us vibes from the "Superman" films of Christopher Reeve. When he responded to "Who are you?" with "A friend," it got is right in the feels. This pairing is already iconic.

The hour opened with a true blast from the past as we moved over to Earth-90, which was the home of the 1990 television series "The Flash," allowing John Wesley Shipp to slip back into his unique Scarlet Speedster duds. One the one hand, we have to say that it's cool to see him suited up again. On the other, it makes us sad to see that his world has been laid to waste.

Is it too much to hope that at least one other character survived. As much as we loved his supporting cast on that show, it was Mark Hamill's Trickster who was truly a character for the ages. He played it with such a manic glee, it's a shame to think he didn't make it out alive.

As for E-90 Flash, we're a little worried he won't make it out of this story alive. Red skies and a Monitor make it sound like a DC Crisis, and those almost always come at the cost of a Flash's life. And the current Flash obviously isn't going anywhere, so the most expendable one would be '90s Flash, who was just a bit ahead of his time with that show.

This also means that every DC show and movie ever produced is probably just another parallel world out there, which means on Earth-66 Adam West and Burt Ward are still the grooviest crime fighters in Gotham City, while somewhere else, the "Teen Titans Go" are waiting for their CW closeup.

Who needs a Batman when you can have a Batwoman. The big moment between the Monitor and the man who will likely become Dr. Destiny (dig that big book) took place in the shadow of Wayne Tower, which means we're in for a trip to Gotham City in the next chapter of this story.

Of course, DC is still being pretty stingy and stubborn about Batman -- or so we've been led to believe -- and so we'll be getting Batwoman, instead. Just as Lois Lane entered the saga Sunday night, Ruby Rose's Batwoman makes her big debut on Monday.

And it's more than just the debut of a fun new character, as The CW is considering expanding into the Bat-verse with a "Batwoman" TV series. If the movie side of things is being stingy and not letting them have a Batman or Superman television series ("Gotham doesn't count as it's technically pre-Batman), then they'll get the next best thing.

And even without Batman, a "Batwoman" television series would have so many characters from the world of Gotham City to play with, including other Batman sidekicks, supporting characters and his wonderful rogues gallery of villains, some of whom we'll meet in Arkham Asylum as this crossover event continues. She looks great, so here's hoping she is great and we can expand the DCW Universe even more!

This one was a nod for long-time fans, but it was still pretty satisfying. Barry finally got his revenge on Oliver for shooting him twice in the back during a training exercise by totally shooting Oliver twice in the back in the exact same way.

The crazy thing is how easily Oliver fell for it. It reminded us of Lucy and Charlie Brown, with Barry totally promising Oliver that this time there's no way he was going to pull the football away. And then thwak, thwak! Two arrows in the back!

Okay, it was petty af, but as Lois put it, Oliver is kind of a jerk. In fact, Oliver got dumped on pretty hardcore in this episode by virtually everyone, but it actually made him seem like a tragic and sad character. He has to channel anger and rage to be the best there is at what he does, but what a sad way to be a hero.

Meanwhile, Barry chases joy and happiness to allow himself to go faster. The question is whether the pair will gain anything from spending this time in each other's lives. The last mega-crossover gave us their combined marriages to Iris and Felicity. Could there be long-lasting repercussions this time as well, only in how they channel their inner light and dark sides?

Almost since the beginning of "The Flash" we've seen this bizarre power-dampening chamber in use, and the question on everyone's mind is ... how do they go to the bathroom? Sure, it's a question we don't often consider when consuming entertainment, but this is a very small room and people spend a very long time in it.

Well, one of the biggest reveals of the night -- and yes, fans were excited about it -- was that there is totally a retractable toilet in the wall. It's also apparently a very vulnerable part of the containment chamber because it took almost nothing for Barry and Oliver to disable the dampeners through it.

Might want to tweak that design a little bit, or go with something a little more low-tech for Barry and whoever else might be spending some time hanging out in there.

That's a good point to end on, too, because this first hour was filled with laughs. Now, "The Flash" is usually the funniest of the CW superhero shows, so we'll have to see if the laughs continue into "Arrow" and "Supergirl" as the three-part "Elseworlds" crossover event continues into Monday and Tuesday.

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