No, that’s not a two-headed snake - it’s much worse than that. It’s actually a massive group of fungus gnat larvae slithering en masse in order to find food. Lovely. Traveling in this snake-like form is beneficial to the juvenile gnats because it reduces the risk of predation.
Check out this video of one group worming its way across a sidewalk:
This is one of those videos that is so disgusting you can’t help but want to watch it again, with a rather screwed up face and the words “nope” or “eeeew” repeating themselves in your head.
Read this: Your Brain on Coffee