How to DIY a unicorn costume?

U can make a paper mache horse head and get a pattern to make the body of the horse from fo fur.

On a white hoodie, make a mane out of rainbow colored tuelle by layering long rectangles (twice the length x twice the height of desired size mane. Sew a long basting stitch up the center (lengthwise) of the layers. Gather the mane until it is the correct length and then fluff the layers until you like the look of it. Hand sew it onto the hoodie. Make the horn out of metallic fabric and stuff it. Don't make it too long or it won't stand up. The tail can also be made out of tuelle strips and sewn onto the back of white sweat paints. Finish with black mittens and black ballet flats.

http://www.wikihow.com/Make-a-Unicorn-Costume