“This is a nutcase who is addicted to fucking with the trains.”

That was how one MTA New York City Transitsource with knowledge of the situation described the latest curiosity to befall the city’s beleaguered subway.

Someone—no one really knows who—has been disrupting the train system, sneaking into cabs, pulling the emergency brakes, and grinding not just one train, but entire lines in the system to a halt during the busiest hours of the day.

And just like that, they then melt into the darkness between the tunnels, waiting to strike again.

And on Tuesday evening, the official New York City Transit account alerted the public to this person’s existence, although the tweet made it sound like yesterday was an isolated incident.

It was not.

This person has an established M.O., the source said, and Jalopnik confirmed this by reviewing internal incident reports. There are at least three so far.

The suspect disrupts service primarily on the 2 and 5 lines from Flatbush Avenue in central Brooklyn to midtown Manhattan. He climbs aboard the rear of the train as it departs a station, unlocks the safety chains, somehow gets into the rear cab, and triggers the emergency brakes. Then, he disappears, most likely through the subway tunnels and out an emergency exit.

Despite striking on average once a week for several months, the person has not been caught.

On April 19, New Yorkers looking to duck out of work a little early to enjoy the unseasonably warm weather may have gotten home a little slower than usual thanks to a disruption on the 4, 5, and 6 lines. To the everyday commuter, all appeared normal; subway delays are a fact of life here in the Big Apple.

But this delay was different.

At 4:17 p.m., a report came in that an “unruly customer” was riding on the back of an uptown 5 train departing Fulton Street. All trains were instructed to hold at the next stop. Upon arriving at the next stop, Brooklyn Bridge, the person ran off the back of the train, onto the platform, and disappeared.

Upon inspection, the train conductor found the safety cables at the back of the train, which prevent people from walking out the back door and onto the tracks, had been taken down.

Eleven minutes later, a New York City Transit employee on duty at 14th St-Union Square (one express stop uptown from Brooklyn Bridge) spotted another “surfer” on the back of an uptown 6 local train as it left the station. The conductor slowed into the next station, 23rd St, and went to the back of the train expecting to find someone.

Instead, the conductor found only the stale subway air and some unsecured safety chains.

Five minutes after that, a 4 train operator spotted yet another “unruly customer,” this time running across the tracks. All trains were held. Again.

Not long after, 19 blocks north at Grand Central, a 6 train conductor noticed the safety chains on the back of his train were loose. He fixed them.

A few minutes hence, now 4:48 p.m., a 4 train’s brakes were automatically activated, causing the train to slam to a stop and creating a train traffic jam during the critical rush hour commute where there’s no room for error. But the operator and conductor determined nothing was wrong with the train and it was fit for service. Someone had pulled the brakes from the rear cab, the one in the back of the train that goes unused when the train is moving in the opposite direction.

Every New York City Transit employee gave the same description of the “surfer” they saw riding the back of the train or darting across the tracks: young, male, wearing black clothing and white sneakers.

Gotham’s newest supervillain had struck again.

This was hardly the first time the unidentified supervillain has terrorized New York City subway riders. He’s been active for several months now, according to reports and the MTA source. This suspect does not obviously aim for world domination or vast riches, but instead targets the most conniving, evil end imaginable: messy commutes.

As a source with knowledge of the situation, who is not authorized to discuss the matter publicly, summarized this person as follows: “This is a nutcase who is addicted to fucking with the trains.”

Who could possibly be so nefarious, you might ask? Who in their right mind would dedicate so much time and energy to toy with New Yorkers’ commutes to work, school, doctor’s appointments? Who would have such disregard for the very fabric of society that he’s willing to destroy the one thing we have left, the safe and secure knowledge that for all the massive problems in this world at least no one is crazy enough to fuck with our commutes just for the fun of it? Who would put themselves at great personal risk, both physically and legally, just to mess with us?

I do not have an answer for you, and apparently neither does the Metropolitan Transportation Authority, which told Jalopnik they have referred the case to the NYPD and otherwise declined to comment, or the NYPD, who did not respond to a Jalopnik inquiry Tuesday evening. (It’s also not immediately clear what charges this suspect could face.)

The only thing we know for sure is he is still out there, somewhere, waiting to strike again.

Today happens to be the day of the MTA’s board meeting, and MTA president Pat Foye confirmed there is a goddamn supervillain or perhaps supervillains on the loose.