Sprites are just an easy-to-use textured rectangle, so there is no function to skew it freely, except maybe using shaders.
If you want to do this, I would suggest using a custom-drawn polygon, by creating a
Node2D, overriding the
_draw() method and using
draw_primitive(). This lets you define exactly where each vertex will be, as well as texture coordinates and colors.
You could also use the