Your body mutates in several interesting ways granting you the powers and training of a Witcher. You know several magical signs which you can quickly and expertly use, you have an inhumanly strong, flexible, quick and durable body, and a very enhanced metabolism as well as severely enhanced senses and natural night vision. You are also an expert of the fighting styles used by the various Witcher schools and have a good understanding of alchemy(but you are unlikely to find the materials used by the art on a non magical world). Lastly you have a very smart and deductive mind, you would be a natural-born detective if you ever applied yourself.
You can choose whether or not you gain white hair or cat-like eyes from this power. Unfortunately, the process which mutated you has also turned you infertile.