Over the years we've seen a lot of gross things on the subway (also cats!) but a picture of something in a subway station, sent in today by Gothamist reader Karyn Behnke, just might be the ickiest thing we've seen underground this year (well, besides this). At least this one isn't actually quite as bad as it looks!

Here's how Karyn describes what you see in that photo, taken at the Nassau G station: "It is quite literally bleeding - oil? I don t have any idea, it is horrifying and it just continues to slowly creep in untouched and unattended to. This picture is from last week, and is what nightmares are made of. Located right as you exit the turnstile, east side of the station."

It certainly does remind us of a monochromatic version of the river of slime in Ghostbusters 2. Or the black oil on The X-Files. But what exactly is it? Well, according to the MTA spokesman Kevin Ortiz, "This is tar that melted and made its way through a drain. Tar and other sealants were used when the station was built to water proof the station. Possible that it melted during the last heat wave over the summer. If it hasn’t been cleaned up already, it will be in the next day or so."

And now you know!