One of the more interesting things about his 'Frankenstein' is in how he did the 'birth' of the creature/ monster.

He build the final version, then burned/ melted it and filmed that process. In the film, he just ran the footage of it melting in reverse, so it looks like it's building. If you look at the film itself, you can see that the fire is also going in 'reverse.' It's really neat.