11/28/2009 05:12 am ET Updated May 25, 2011

Improv Everywhere Strikes Again, Floods Brooklyn With Invisible Dogs (SLIDESHOW)

Improv Everywhere, the group that brought you Grand Central Freeze and No Pants Subway Ride, struck again on Sunday. The group's founder, Charlie Todd, didn't give anything away when he asked his growing number of "agents" to show up at an old belt factory in Boerum Hill, Brooklyn on Sunday afternoon.

At 2pm sharp, Todd announced that participants would be given dogs to walk around the neighborhood for the afternoon--invisible dogs. The gathering space had been the factory where the collars were manufactured in the 1970s before the factory was abandoned. Now the warehouse looking structure will be turned into The Invisible Dog art space, and this was to be its inauguration.

Over a thousand so called agents (estimated at 2,000 by Todd) lined up to receive their invisible dog leashes and were told to act natural as they walked their make-believe canines around Brooklyn.

Striving to live up to Improv Everywhere's rock star reputation, participants took their mission seriously, naming their invisible friends, stopping next to fire hydrants where invisible dogs would mark their territory, and using plastic bags to clean up after their pet's odorless scraps.

Walking the Dog: 2,000 Invisible Dogs Unleashed in Brooklyn

"What's going on?" was the refrain of onlookers, asked both of participants and often of nobody in particular.

When confronted about his floating leash by a mother and her child, invisible dog walker Sam Utne responded kindly, "It stopped raining, so I thought I'd take Rex out for a walk. Do you want to pet him?" Unfazed, the young boy bent down and moved his hand through the air inches above the empty leather dog collar.

Not all onlookers were so willing to play along.

"Get a real dog!" shouted a man from the passenger window of a black Escalade, who along with a few others seemed to feel that the joke was on them.

Other onlookers seemed stuck in a state of befuddlement, begging every person attached to a leash to "tell the truth" about hordes of people with floating leashes. These people were rarely satisfied with whatever improvised response they received.

For the most part, participants and onlookers alike spent the two hours paying heed to something that wasn't there and, in doing so, found an excuse to pay more attention to each other.

If you were there, upload your photos by pressing the "Participate" button below.

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