One of my favorite Frankenstein sequels is the short story “Black as the Pit, From Pole to Pole” by Howard Waldrop and Steve Utley. It picks up where the novel left off with Frankenstein’s Monster wandering across the polar ice cap. He has discovered that Frankenstein made him too well – the ice and cold won’t kill him. He doesn’t want to try drowning himself – it might not work. So he keeps walking – right into the northern opening to the hollow earth.
He makes his way through the Earth encountering all manner of monsters, beasts and weirder things, conquers kingdoms, finds love, and sows fear and destruction in his path. Eventually he comes out at the South Pole. I liked the story so much that I bought the book Custer’s Last Jump just so that I wouldn’t have to check it out of the library the next time I wanted to read it. One of these days I’ll have to get around to reading the other stories that keep it company.