Body horror has become more mainstream thanks to Demi Moore's incredible performance in The Substance. The 2024 film is a riveting look at beauty standards, the question of how someone can grow older in Hollywood, and how fame can change someone. There are more than a few gory scenes as Moore's character Elizabeth Sparkle takes a strange drug and sees her entire world change. The movie is so popular that there are a few interesting The Substance fan theories and many are still unpacking the ending.