Ingersoll Lockwood invented the fictional character Baron Trump in 1890 for a two-part sci-fi/fantasy series about a privileged boy who undertakes a sequence of fantastic voyages. The style of the Baron Trump series—a mix of fantasy and young-reader-oriented science fiction—anticipated and may have influenced L. Frank Baum's Oz series. The second in that series, Baron Trump's Marvellous Underground Journey, describes Baron's trip to the earth's interior via an opening in the Russian Arctic. During the journey, Baron and his dog Bulger encounter many lost races, including the Transparent Folk and the Rattlebrains. The unusual prescience of Ingersoll's narrative has given rise to a conspiracy theory that U.S. President Donald Trump has had access to a time machine.