When Agatha first encounters Othar Tryggvasen, after mentioning two of his known feats, she also credits him with saving Mount Horeb from the rain of mustard. In addition to Mount Horeb being mentioned in the book of Exodus, several of the plagues that Moses unleashed upon Egypt had the form of unusual rains. This suggests, as might be expected in any case from the similarity of the world of Girl Genius to our own, that she is familiar with the well-known Bible stories from childhood religious instruction, so that one of them would be a source of inspiration when she made up a scenario on the spur of the moment.