At least one alligator really does live in New York City’s sewers.

Cops apprehended an 18-inch gator that crawled out of an overflowing Astoria storm drain and hunkered down beneath a parked car this afternoon, delighting onlookers and giving fresh meat to the urban myth that the carnivorous critters are living below the Big Apple.

The scaly spectacle began just after 3 p.m., when a passerby spotted the reptile on Newtown Avenue near 29th Street and yelled “Crocodile!”

“That’s the craziest thing I’ve ever seen,” marvelled Elizabeth Ferguson, 25, who has lived on the block for three years. “He was really small, but mean looking.”

Cops couldn’t verify onlookers’ claims that the animal crawled from the sewers — a big-city myth that inspired the 1980 B-movie “Alligator,” and others — but were baffled as to where it came from.

“It’s a big mystery,” said police spokesman Officer James Duffy. “It could have been dumped from a car or it could have come out of a sewer.”

The police Emergency Service Unit lassoed the animal and bound its snout with tape. The caged gator was kept at the 114th Precinct until it was picked up by Animal Care & Control.

A spokesman for animal control said the alligator would be taken to a licensed rehabilitator or reptile sanctuary.

Crocodiles and alligators have called New York home in the past, most famously in 2001, when the city was captivated by a caiman that eluded authorities in Central Park for a week. In 2003, cops caught a 4-foot croc that was wandering around a Queens park.

But today’s encounter had more than a few cops snapping cell phone photos.

“You could say it was one of those quirky things,” Duffy said.

Some experts have called the city’s sewer system a “natural swamp” warm enough to attract gators, but few think they could survive for very long.

No one has claimed the alligator as of this evening.