Johann Konrad Dippel was rumored to create potions, perform electrical therapies, and partake in gruesome experiments involving stolen body parts from the graveyard. Born in the Castle Frankenstein in 1673, it’s disputed whether or not he was the inspiration for Mary Shelley’s mad scientist of the same name, who did some cadaver experiments of his own.
What is sure about Dippel is his colorful career as an alchemist. He attached his name to Dippel’s Animal Oil, which he discovered from the destructive distillation of animal parts and claimed as a universal medicine. The animal oil came at the end of a wave of popularity for Iatrochemistry, which had moved alchemy from the search for creating gold to finding new medicines. The unpleasant taste and smell, as well as the progression of medicine, made Dippel's oil fall into disrepute by the end of the 18th century.
Dippel later helped set up a laboratory in Berlin for making gold and, at one point, he ended up in prison on a Danish island for seven years due to political activities. In 1734, he finally had a stroke and died at the Castle Wittgenstein near Berleburg, although his friends claimed he was poisoned. By his own hand or that of another, it is unclear.
The Castle Frankenstein is now in ruins, with only two towers, a restaurant and a chapel remaining. However, the perhaps mythical connection to Mary Shelley’s novel "Frankenstein" keeps it a popular destination, especially for Halloween. A popular annual party was started there by American soldiers stationed near the castle in World War II. Until it was deactivated in 2008, the US Army's 233rd Base Support Battalion in Darmstadt conducted an annual Frankenstein Castle run which finished at the tower. The castle was featured in an episode of "Ghost Hunters International" which aired in February of 2008.