something is growing in my vodka

Hello, I recently found an old bottle of vodka that I had opened then closed properly and stored it in the closet. It is maybe one or two years old.

It seems to have some sort of growth that resembles algae. Its very stringy and is a light black color when removed.

I did not think this was possible. I was hoping a biologist would know what it was or what is going on here. Can I drink it?