"Can anybody explain this or are just living in full blown Gotham rn," X user Dan Pantelo wrote on the social media platform. He posted a video showing a pool of green liquid next to a smoking road flair.
In another photo, which showed the green liquid spilling out over a steaming manhole cover, he said "There's literal green sludge bubbling up from the ground next to the World Trade Center right now."
Users contributing to "Community Notes" on X and in Mr Pantelo's comments pointed out that the liquid likely had been dyed green to assist city workers in detecting leaks in the city's sewers.
Despite the reasonable explanation, X users were quick to point out that the green liquid resembled the ooze that created the Teenage Mutant Ninja Turtles, while others referred to the Ghostbusters II slime that made everyone in New York angry.
Naturally, it could not be the latter; the Ghostbusters II slime was pink, not green.
"As a Gen Xer, here's what I know about underground sludge in New York: green = cool mutants, pink = angry ghosts," one X user wrote.
Another user added: "Eric Adams is ordering aides to bring him the Ghostbusters."
A third user, Alice Tovey, also took into account the white steam emerging from the manhole where green slime was spilling out and — referencing the Vatican's tradition of releasing white smoke at the selection of a new Pope — wrote that a "new Ninja Turtle has been elected."
Unfortunately, the reality is much more mundane. The striking fluorescent colour used in the dyes is intended to help spot leaks in low-light situations, like sewers or other underground pipes.
In addition to fluorescent dyes, certain antifreeze variants — typically used in older model vehicles — bear the same bright green colour.
The city hasn’t publicly commented on the liquid’s origins yet, but The Independent has reached out for comment.
It's far from the first time New Yorkers have reported seeing green sludge; earlier this year subway riders had to step over streams of fluorescent green slime on their way to their trains in Prospect Heights, according to the New York Post.
While the same Teenage Mutant Ninja Turtle and Ghostbusters jokes were tossed around during the March sighting, the slime had the added benefit of adding some green to the subway just in time for St Patrick's Day.
Join our commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies