This one has been sitting on my to-do list ever since I watched the series. I love Celty's Dullahan form (even if her dress seems a bit plain) and it was a perfect costume to pull together when money was tight.
The head is just a Styrofoam wig head that I painted and added a wig to. The wig was cannibalized from a prior costume due to a styling mishap, so no loss there.
The cloak is made from black crushed velvet (which I thought had a lovely swirl effect that resembled smoke). I modified an easy cape pattern to create a narrower fit.
The dress is made from Gabardine (dress slacks material) since it resembled a simple woven fabric she might wear. Because her dress felt very plain, I added more red than the reference image originally had. Only the red accent on the bodice is from the original reference; the neckline, sleeves, and skirt hem also have deep red panne velvet trims/accents.