“Green sludge” was spotted emerging from manholes around the World Trade Center in New York City this week.

An X user posted photos and videos of the situation, that soon went viral on Thursday.

He then added an update Friday and stated the goo was “still there, people are walking through it casually.”

“[S]ometimes a small crowd gathers around and stares at it,” he wrote.

X users were quick to poke fun at the unusual substance on the New York City street.

“Are there any turtles in sight?” one user asked, referencing the iconic pizza-loving “Teenage Mutant Ninja Turtles.”

Another added that the mysterious substance was “Ooz and it’s how the Ninja Turtles came about.”

The mystery of the green goo was later solved with an X community note that stated the liquid was just “water full of green dye.”

“Plumbers frequently use harmless, fluorescent green dye to detect leaks in plumbing and sewage systems,” the note read.

U.K.’s Daily Mail spoke with a worker at a nearby New York restaurant who stated that “city workers were testing the hotel’s sprinkler system across the street” and used the green dye.

This isn’t the first time the green liquid has struck the city.

A similar incident occurred last March in a Brooklyn subway station, according to the New York Post.

At the time, a representative with the Metropolitan Transportation Authority told the outlet, “Unfortunately, [there were no] reports of anyone gaining superpowers and/or any teenagers becoming sword-wielding turtles.

“I haven’t heard any news of any particle accelerator explosions or lightning storms,” the representative said.

This article appeared originally on The Western Journal.