In many ways Frozen represents the new era of Disney, but the modern megahit has actually been in the works since before you were born. Just before the release of Snow White and the Seven Dwarfs in 1937, Walt himself was looking into an adaptation of Hans Christian Anderson's The Snow Queen. Over the course of nearly 70 years, this movie became Frozen -- but the original Danish fairy tale is almost unrecognizable compared to the adventures of Anna and Elsa.
Part of the problem Disney ran into initially was that The Snow Queen is a pretty dark story. It begins with an evil mirror shattering, its shards finding its way into a young boy named Kay, who is corrupted by its black magic. Kay is then kidnapped by the Snow Queen and kissed two times -- the first time to help him withstand the cold, the second time to brainwash the boy into forgetting his family. It is said that a third kiss would kill Kay outright, so basically the Snow Queen has a gun to her captive's head for the entire story. Only through the brave actions of Kay's young neighbor Gerda is the Snow Queen thwarted by, what else, the power of love.
Of course, Disney fans know that tons of the original fairy tales were even more disturbing in their own right -- what with the original Ariel dying of a broken heart and dissolving into seafoam. The characters themselves were also an issue, specifically the Snow Queen, who proved to be tough to portray as a likable (or at least watchable) personality. For a while there, the closest Disney came to a real adaptation was in the late 90s. This was back when the movie was still going to be 2D, hand-drawn animation.
This version was at one point known as "Anna and the Snow Queen" (which oddly enough, is what the Japanese title for Frozen translates to). The little we do know about the story at this stage comes from concept artists like Mike Gabriel. In AatSQ, Anna finds a buried ice palace in the wilderness, a place thought only to be a legend. The thrust of the movie would begin when Anna accidentally ressurects the Snow Queen, who had been frozen in a block of ice. The two weren't sisters, and presumably didn't sing adorable but depressing songs about building snowmen.
Un-Elsa herself was also much different; the concept artist described her as a "Vegas showgirl type," which you can see above. Though Josh Gad was still in the picture as an early form of Olaf, Megan Mullally was set to play the Snow Queen instead of Idina Menzel; avid TV-watchers might know Mullally as Karen on Will & Grace or Tammy 2 on Parks and Recreation. Though Sexpot Elsa obviously didn't make it to the final product, if you want to see more of that, well, you're already on the internet.
As we see from Claire Keane's concept art, the Snow Queen maintained a kind of rockstar/showwoman design for some time. On the left you can see Bette Midler's influence on Keane's art, and the image on the right is inspired by Amy Winehouse.
You can tell that making Elsa something of a larger-than-life personality was an attempt to make her more endearing to viewers; though that didn't exactly help her relatability problem. But that's when the filmmakers had the bright idea to make the Snow Queen and Anna a pair of sisters.
Turning the two main characters into siblings did a lot to alleviate the problems with Frozen. Before, the Snow Queen was basically an evil genie to Anna's unwitting and unlucky Aladdin. By changing the story so that the two grow up together, the pair already have a built-in relationship; you know there's inherent good in Elsa because we see her as an innocent child.
That being said, Elsa was still blue. And she was still the bad guy.
Elsa is shown to be immensely powerful in Frozen, but we get the feeling that she's probably holding back. After all, this is the same person who created sentient snowman life without even realizing it. If she put her mind to it, she could probably summon an entire army of snowy hencmen to do her bidding and take over Arendelle.
And as is evident in this deleted scene, that was in fact the plan for Evil Elsa.
The production team was well into the storyboard phase (and maybe even beyond that), and Elsa was still a straightforward antagonist. Then it came time to record one of Disney's most ear-stabbingly catchy songs ever. "Let It Go" was supposed to be the ballad belonging to a villain, but when the filmmakers listened to it they realized something: The bad guy had suddenly become too relatable. Elsa's desire for freedom to be herself sounded much more like something a hero would sing about, and so Let It Go became the tipping point for Elsa's eventual transformation from icy Cruella De Ville type to a misunderstood but well-meaning "monster" like Rogue from the X-Men. At some point down the line, they also decided Elsa shouldn't have the skin pigment of a suffocated Smurf.
We'll never get to see that Evil Elsa movie. The best we can hope for is fighting a huge snowman army in the next Kingdom Hearts.
Tristan Cooper's early evil version can be found on Twitter.