I thought I could get away with recycling last year’s costume, but my son decided he wanted to be a ninja.
I figured the hardest part would be the mask. Then I found this tutorial on Sew2Pro. I took the short cut of cutting a slit, folding over and sewing the edges instead of using bias tape.
The rest of the costume is a pair of pajama pants, a long-sleeve T and a vest top that I made longer. I did find a free kimono top pattern at Habitual, if you want something a bit fancier.