Photographs by Evan R. Wexler

Perched high above an industrial stretch of East Williamsburg, a menacing robot nine feet high and seven feet wide surveys the street below, watching cars steal past graffitied factory buildings as if they were prey. Its fierce head sways and dips when a wooden rudder protruding from the back of its neck catches the breeze.

This is the Brooklyn Griffin. It almost never was. An earlier edition was destroyed on orders from an unsympathetic building manager.

“We managed to salvage a whole hand and two thumbs,” said one of the two visiting British artists who built the griffin. The rest was relegated to the trash.

The two men, who make art under the names of Jimmy Bumble and Leonard White, traveled to the United States from London as part an art collective called Giant Robots that constructs walking, talking robots made almost entirely from found objects.

But the two, former movie-set builders, ran into legal trouble two weeks ago when they were caught building the wooden structure atop a building on JohnsonAvenue near the Williamsburg-Bushwick border.

“They were grafittiing and decided that my roof happens to be a lumberyard,” Yosef Laine, the manager of the building, said by phone.

They were arrested at Mr. Laine’s request and charged with criminal trespassing. After 26 hours in police custody, they were brought before a judge, who said the charges would be dropped in six months if they stayed out of trouble, according to prosecutors.

Only splinters remained on the rooftop upon their return. Mr. Laine said that “one of my guys” had smashed the sculpture.

With a week left before their flight back home Aug. 27, Mr. Bumble and Mr. White stumbled upon a group of men painting murals on another decrepit factory building nearby.

Among them was Jay Leritz, 42, who manages several buildings in the area and invited the artists to build their robot on top of his restaurant, Yummus Hummus, on Waterbury Street between Meserole and Scholes Streets.

“We just started talking, and I said, ‘All right. I would love one of those around here,’ ” Mr. Leritz recalled.

The artists persuaded the skeptical landlord, Morris Green, that the robot would not damage the roof or injure anyone.

“They promised me that it was safe and that there were no hazards, so I let them continue,” Mr. Green said.

The robot soon began to take shape. The artists used wooden shipping pallets from Mr. Leritz’s design studio to build the bulk of the body in hexagon-shaped segments; they broke discarded skateboards in half to create a feathered mane; and the leftover thumbs from the previous robot were turned upside down and became wings.

Because of safety concerns and logistics, the griffin does not have locomotive abilities, aside from the moving headpiece.

The artists did not initially know what they were building, they said, since they do not sketch their robots beforehand. The concept remained unclear until one man stopped them while they working in the street.

“He said, ‘Oh, look! The Brooklyn Griffin!’ ” Mr. White recounted. “And I said, ‘Yeah! This guy’s named it,’ and it really is a griffin with wings, a beak and claws. It completely ended up being that without any concerted effort.”

The robot-makers said they hoped to come back to the still largely desolate block in the fall to make the griffin a mate, and possibly a whole family.

“This place is on the cusp of something exciting,” Mr. Bumble said.