Bullseye!

Wiki:

A Freischütz, in German folklore, is a marksman who by a compact with the devil has obtained a certain number of bullets destined to hit without fail whatever object he wishes. As the legend is usually told, six of the Freikugeln, or "free bullets", are thus subservient to the marksman's will, but the seventh is at the absolute disposal of the devil himself.

Various methods were adopted in order to procure possession of the marvelous missiles. According to one, the marksman, instead of swallowing the sacramental host, kept it and fixed it on a tree, shot at it and caused it to bleed great drops of blood. He then gathered the drops on a piece of cloth and reduced the whole to ashes, and then with these ashes added the requisite virtue to the lead of which his bullets were made. Various vegetable or animal substances had the reputation of serving the same purpose.

Stories about the Freischütz were especially common in Germany during the 14th, 15th and 16th centuries; but the first time that the legend was turned to literary profit is said to have been by Johann August Apel in the Gespensterbuch or Book of Ghosts. It formed the subject of Weber's opera Der Freischütz (1821), the libretto of which was written by Johann Friedrich Kind, who had suggested Apel's story as an excellent theme for the composer. The name by which the Freischütz is known in French is Robin des Bois.