My grandfather used to tell my cousins and I wicked stories about wraiths and ghosts, two of which I remember most were the Roggenfrauen and Bilwis. I took elements from both of those creatures to create this.
For my non-German followers (or even some German ones, as legends change depending on who is telling them), both the Roggenfrau and the Bilwis are Feldgeister, or field ghosts/spirits. The Roggenfrau (or Rye woman, but it has many other names) preyed upon children that ventured into her fields, and tormented farmers at harvest. She is said to have a shadowy form, and can sometimes show herself as a wolf. Her arms a long and her fingers are made of iron.
The Bilwis are not quite a malevolent, but can still be nasty. What struck me the most about them was they has "flying hair" or hair that blew upwards as if the wind did not affect them. While they also are field spirits, they have control over the winds.
Now you will never see an empty field the same way again!