La Mancha Negra (The Black Stain) is a mysterious black substance that has oozed from roads in Caracas, Venezuela, first appearing in 1986.[1] Since the appearance of La Mancha Negra, it has caused multiple car accidents and claimed many lives.[2] Determining the cause of the substance has proven difficult and there are still no definitive explanations,[3] despite almost two decades of study and millions of dollars spent identifying it.[4]