Harry Potter fans will know Nagini as Lord Voldemort’s giant snake and also one of the horcruxes that contained a slither of his wretched soul.
While the serpent met her end in Harry Potter and the Deathly Hallows when Neville Longbottom cut off her head, her origin has been something of a mystery.
But now the new Fantastic Beasts 2: The Crimes of Grindelwald trailer has revealed she used to be witch.
Claudia Kim plays the humanoid form of Nagini in the film and some fans have been wondering is she’s an Animagus like Peter Pettigrew aka Wormtail.
However JK Rowling herself, who wrote the script, has revealed Nagini is actually a Maledictus.
A fan asked: “So a Maledictus is pre-destined to be evil? They were born that way, kind of speak.”
The author replied: “Not at all. The slow transformation into a beast is beyond their control, but they aren’t destined to be evil.
“They’re different conditions. Maledictuses are always women, whereas werewolves can be either sex.”
She added: “The Maledictus carries a blood curse from birth, which is passed down from mother to daughter.”
In the new Fantastic Beasts film Nagini is main attraction at a wizarding circus and freak show known as Circus Arcanus.
Presumably there will be a point where she can no longer turn back into a witch.
Kim has teased her role, telling Entertainment Weekly: “It will be so interesting to see another side of Nagini.”