Frost

Evil Elsa, or sasuke!Elsa as some like to call her(because of her black hair I presume), with Anna. This could be considered as an AU, or maybe even future take. and the reason why Anna's hair is white, well I'm not so sure, but basically the idea is that Elsa had struck her heart with ice, but that crystal she is wearing is something that's keeping her from being completely turned into an ice figure.
And here's a little GIF  showing the progress work, this took me about 4 hours to make sta.sh/01dxegk22098