NEW YORK, April 7 (UPI) -- New Yorkers have been walking city streets with polar bears since a local artist created a series of plastic inflatable bears that pop up as subways rush past.

Brooklyn artist Joshua Allen Harris, 31, came up with the idea for his pop-up bears after seeing an old piece of hazard tape blowing over an underground subway vent, the New York Post reported Monday.

"When I set them up, the surprise brightens people up. They say, 'I can't have a bad day now. I have seen that'," Harris told the newspaper.

The blow-up bears, constructed from old plastic bags, reportedly have been enthusiastically welcomed by city residents and have even appeared on an arts Web site.

"It is the most inventive thing I have seen in a long time. It is amazing how (a bag) comes to life when the air moves through it," said Trish Tillman, 33, a New York graduate student who submitted photos of the bears to the Wooster Collective art Web site.