The Magician's Monster is a mythological monster purported to be living in the forest around Castle Frankenstein, outside of Darmstadt, Germany. It is believed to have been derived from the myths and legends surrounding the historical alchemist who did experiments in the castle, Johann Conrad Dippel, who in turn is speculated to have inspired Mary Shelley, who wrote Frankenstein. Mary visited the region in 1814, two years before she began writing her Gothic novel, while touring Europe with her future husband Percy Shelley. Physical descriptions of the Monster are sparse, but like his counterpart in Shelley's novel, he is said to have been stitched together from various body parts and brought to life with a lightning bolt. He also is reported to have a ghastly appearance traditional to variations on the Frankenstein myth.
The following information about the Magician's Monster is taken from an essay by A.J. Day, from his translation of the anthology Fantasmagoriana (Tales of the Dead) -- the volume that inspired Mary and her friends to write ghost stories that ultimately led to her creation of Frankenstein. Day reveals that Mary Shelley's step-mother, Mary Clairmont, was a translator for the Brothers Grimm, with whom she was in frequent contact:
In his book Burg Frankenstein, Walter Scheele discusses the contents of a letter written by Jacob Grimm to Mary Clairmont, which few have had access to. In the letter, Grimm reports of a "Horror story that should, under no circumstances, be published in the fairy tales collection because it is nothing more than a horrible story. The people who live at the foot of the Frankenstein ruins tell their children stories of the occurrences in and around the castle to frighten them into avoiding the castle and nearby woods during the winter evenings."
According to the story, a magician was supposed to have lived at the castle and used parts of corpses from the cemetery in the valley to create a monster, which he put in the castle prison. One day in November, the monster broke out of the prison, killed his creator, and fled into the forest. He now lives there alone, an enemy of everyone. Because of his loneliness, the monster grabs little children who wander alone in the forest and drags them back to his hideaway. There, he plays with them until he becomes bored. Then he dips the unfortunate children into boiling water and eats them.
Another variation of the story, from Miranda Seymour's biography Mary Shelley, mentions “gruesome tales of a cannibal monster who, in times long past, used the grim little castle as his headquarters,” suggesting sightings within the castle as well as in the forest surrounding it.
Every Halloween, Dippel's legacy is celebrated at Castle Frankenstein, which is visited by thousands of costumed visitors. Dippel's ghost is said to frequent the castle's tower, rattling the bones of his victims as he calls out for his Monster in the surrounding forests. No sightings of the Monster have ever been confirmed -- but the children who live in the area know to this day to stay out of the woods in the winter, lest they become his hapless victims.