This whole black goo symbology stems from something called the Grey Goo Theory. The following is from Wikipedia: “Grey goo (also spelled gray goo) is a hypothetical end-of-the-world scenario involving molecular nanotechnology in which out-of-control self-replicating robots consume all matter on Earth while building more of themselves, a scenario that has been called ecophagy (“eating the environment”, more literally “eating the habitation”).