Holy Horcrux! Harry Potter fans are giving the new The Crimes of Grindelwald trailer — and author J.K. Rowling — a major side-eye after Warner Bros. unveiled the identity of a character portrayed by actress Claudia Kim.

When the trailer for the upcoming Fantastic Beasts sequel premiered Tuesday (September 25), followers of the franchise were shocked to discover Kim is playing none other than Nagini, a circus performer suffering from a transformative blood curse that allows her to shift from human to snake at will. Years later, however, Nagini's affliction turns irreversible, and she eventually becomes Lord Voldemort’s faithful slithering serpent — as well as a Horcrux.

Watch below:

Kim, who kept hush about her part in the upcoming fantasy film out November 16, told Entertainment Weekly she's excited for viewers to see a more vulnerable side to Nagini that deviates from the character's villainous role "as a Horcrux" in previous Potter movies.

However, not everyone shares Kim's enthusiasm.

Fact is: Rowling's fans are ticked off about the reveal — with no offense to the South Korean star, of course — because of the dark, problematic nature of Nagini's origins in the Harry Potter universe.

"Now that we know nagini is a cursed woman and not a snake, voldemort keeping her as a pet for years and making her a horcrux is... f--king disgusting," one angry user tweeted. Another argued the shocking reveal was a poor attempt at diversifying Rowling's "white cishet" universe: "having nagini be portrayed by an asian actress, and the conotations [sic] of that is disgusting and i’m so angry."

Many others contended that an even better (and less offensive) surprise could have involved Dumbledore, whose sexual identity has been much-talked-about in the fandom after Rowling revealed the wizard was canonically gay: "Typical that they will make voldemort's snake girlfriend a plot point and not speak a word about dumbledore being gay."

Scroll down for more fiery reactions to the trailer on Twitter, below:

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