History Series / Elseworlds2018

A reality-bending experiment by Dr. John Deegan (Creator/JeremyDavies), a doctor from Gotham City's Arkham Asylum, causes [[ComicBook/GreenArrow Oliver Queen, aka the Green Arrow]] (Creator/StephenAmell), and [[Franchise/TheFlash Barry Allen, aka the Flash]] (Creator/GrantGustin), to involuntarily swap lives and identities. With the help of [[Franchise/{{Supergirl}} Kara Danvers, aka Supergirl]] (Creator/MelissaBenoist), the only person who recognizes the switch, Oliver and Barry have to embrace the other's abilities, assemble a team of heroes from across TheMultiverse and set things right.

"Elseworlds" introduced ComicBook/{{Batwoman}} (Creator/RubyRose) and Gotham City — a first for the Arrowverse— as well as ComicBook/LoisLane (Creator/ElizabethTulloch), Nora Fries (Cassandra Jean Amell) and [[ComicBook/CrisisOnInfiniteEarths The Monitor]] (Creator/LaMonicaGarrett), while Franchise/{{Superman}} (Creator/TylerHoechlin) returned for his first appearance in an Arrowverse crossover. In a very surprising twist, Creator/JohnWesleyShipp's [[Series/TheFlash1990 Barry Allen]] also showed up. The crossover set up Batwoman's [[Series/Batwoman2019 own series]].

* GenderBender: A strange version in the ''Series/{{Elseworlds|2018}}'' crossover between three [[Creator/TheCW CW]] series. Deegan has rewritten reality so that he is Superman. However, Kara soon realizes that technically he is not actually Superman, but rather a male version of herself, based on the scans that the AMAZO robot took of her. This is because she is from Earth-38, and the Book of Destiny that Deegan used to rewrite reality only contains information on things from Earth-1. Kara mocks him for being too scared to just go all the way and become her. The three different series and episodes are:
** ''Series/TheFlash2014'' "[[Recap/TheFlash2014S5E9ElseworldsHourOne Elseworlds Part 1]]"
** ''[[Series/{{Arrow}} Arrow (2012)]]'' "[[Recap/ArrowS7E9ElseworldsHourTwo Elseworlds Part 2]]"
** ''Series/Supergirl2015'' "[[Recap/Supergirl2015S4E9ElseworldsHourThree Elseworlds Part 3]]"

** Also, the Book of Destiny very strongly resembles the book that Destiny of the Endless always carries in the Creator/NeilGaiman ''[[ComicBook/TheSandman Sandman]]'' comics. Making it the...[[DepartmentofRedundancyDepartment Book of Destiny]]. This is particularly appropriate as ''Sandman'' retconned the gem that gave Dr Destiny his DreamWalker powers as being part of Dream's regalia. So he still has powers from an artefact that belonged to one of the Endless, just a different one.

* CanonWelding: Happens to the 1990 Flash further. In his series, he was the only real-life superhero in his world and Batman and Superman were [[MythologyGag fictional characters]] (as shown by their [[Film/SupermanTheMovie movie]] [[Film/Batman1989 posters]]). In a stinger before the crossover proper, it's established that Earth-90 has (or [[KillEmAll had]]) several other real superheroes besides him, like versions of Green Arrow and Stargirl. Also, he generates lightning when he runs now, while he didn't in his show because the Speed Force concept wasn't a thing yet.

* AbsenteeActor:
** This is the first crossover since 2015 ''not'' to feature [[Series/LegendsOfTomorrow the Legends]] (or characters who will become Legends) [[note]]The 2015 crossover was a BackdoorPilot for ''Legends''[[/note]] who will be sitting this one out; though Gary makes a cameo in part 3. Their concurrent episode has them casually blowing off the other heroes' distress calls while their personalities have been time-altered. A later episode has them still regretting not showing up.
** Of the participating shows, very nearly all the supporting characters are involved. The exceptions are [[Series/TheFlash2014 Cecile, Nora and Joe]], [[Series/{{Arrow}} Dinah, Rene and Laurel]] (though Laurel got mentioned in Gotham), and [[Series/{{Supergirl 2015}} Nia & Lena]]. However, only [[Series/TheFlash2014 Barry, Cisco and Caitlin]], [[Series/{{Arrow}} Oliver & Diggle]], and [[Series/{{Supergirl 2015}} Kara]] appear across all three parts.

''Elseworlds'' is a 2018 {{television serial}}, and the Series/{{Arrowverse}}'s fifth annual {{crisis crossover}}, told across episodes of ''Series/{{The Flash|2014}}'', ''Series/{{Arrow}}'', and ''Series/{{Supergirl|2015}}'', starting December 9th and concluding on the 11th.

* {{Crossover}}: The fifth annual for the Series/{{Arrowverse}}. This time, the Legends of Tomorrow sit out the crossover and instead the featured heroes are [[Series/TheFlash1990 '90s Flash]], [[Series/TheFlash2014 Modern Flash]], [[Series/{{Arrow}} The Green Arrow]], [[Series/Supergirl2015 Supergirl, Superman]] and [[Series/Batwoman2019 Batwoman]].