Harry witnesses a traditional Walpurgis Night celebration in the Black Forest. He sees the women brew magical drinks and recite a curious spell: the Hexeneinmaleins. It is a poem from the first part of "Faust" by Johann Wolfgang von Goethe. By the way, the writer, who was born in Frankfurt am Main, lived and worked in Weimar for most of his life - not far from the legendary Harz Mountains.

In Goethe's world-famous work, Faust is an aging scientist who is dissatisfied with his life. In his quest for the deepest knowledge of the world and life, he makes a deal with the devil and promises Mephisto his soul if the devil makes him happy and satisfied. In one scene, Mephisto takes Faust to a witch's kitchen. The witch gives Faust a potion that is supposed to make him young and desirable. To enhance the potion's effect, the witch recites the mysterious witch's riddle. Incidentally, some clever people discovered the verse hides the solution to a mathematical riddle. But Harry probably would not be in the right state of mind for that now, as he first has to figure out how to get out of the time loop.