Ever feel like you aren't totally yourself? Well, maybe you aren't. In this video, we explore the idea of human chimeras. In mythology, the "Chimaera" was a beast made from different animals combined into one. But in biology, a chimera is a single organism whose body is made from parts of two or more genetically distinct individuals of the same species. Biological chimeras were once thought to be rare, but modern genetics has shown us that these genetic mashups are so common, that you yourself may actually be a chimera. And even if you don't have part of another body in you, your body is certainly not just one thing. We also discuss the idea of mosaicism and how it relates to cancer, Tasmanian devils, and circus sideshow attractions.