it's “Walpurgis"

[jeff of pa]

Walpurgis Night (Walpurgisnacht) is celebrated annually on April 30th (the eve of May Day) in Northern and Central Europe, particularly in Germany, Sweden, and the Czech Republic. Known as the "other Halloween" or "Witches' Night," it marks the shift to spring by blending pagan rituals, such as large bonfires to ward off evil spirits, with the legend of witches gathering on the Brocken mountain in Germany

Walpurgis Night a British lady went from Catholic saint, to Germanic goddess, to witch , according to the belief of millions of people, the devil was abroad—when the graves were opened and the dead came forth and walked. When all evil things of earth and air and water held revel.