E.T. Thorpe was giddy. On the same day last week, at two different corners in one of Philadelphia's most distinguished neighborhoods, he came face-to-gut with a creature of mystifying proportions.

"Did you know," Thorpe said, with artful eyeglasses and a bemused smile as he teased from the doorway of a Pine Street framing shop, "there were two dueling rats?"

Scabby the Rat, the two-story-tall inflatable rodent of labor-movement legend, was on double duty in Center City, serving as a monstrous prop of protest that labor leaders say is an essential ploy in hostile times.

In fact, on Monday last week, a pair of Scabbys - one gray, one yellow, each deployed by a different union - stood protest on South 13th Street in Washington Square West. They sneered grotesquely at construction projects employing nonunion workers while residents of colonial streets and stately brownstones nearby passed on foot or bicycle.

One menaced at a six-story apartment complex going up on Lombard Street. A few blocks north, at Spruce, another hovered over the conversion of the dilapidated 12-story Parker Spruce Hotel into a Fairfield Inn.

"I actually sort of love them," Thorpe said.

Charlotte Veazie was less charmed.

Awakened by the incessant wailing of a baby, a recording employed with the rat, Veazie peered out the second-story bedroom window of her South 13th Street rowhouse to see Scabby staring in.

"It was kind of mean-looking, to tell you the truth," said Veazie, a 69-year-old widow.

Whether they consider it a clever invention of a labor movement under siege or as adolescent high jinks interfering with profit, few people can argue with Scabby's staying power.

A quarter-century after being invented by Chicago-area union folks, the big fake rat, with garish features that sometimes include bloody nipples and scabs, is as ready an ally to unions as an in-house lawyer.

Unknown numbers of the deflated, Moon-Bounce-like rodents are tucked away in union sheds across the region, just waiting to be hauled out, hooked to a generator, and pumped up like a foreboding lawn ornament wherever labor leaders are seeking leverage.

"We have four rats," said Ryan Boyer, business manager of Laborers District Council, whose members boast one rat per local in Southeastern Pennsylvania.

One has been on Parker Spruce patrol for maybe six weeks.

"A picture," Boyer explained, "speaks a thousand words."

Tapan Das, a spokesman for the Parker Spruce developer Shree Sai Siddhi Spruce L.L.C., said work had stopped on the building, the developer blaming laborers and union bricklayers for illegally blocking the entrance. A lawsuit has been filed to end the picketing.

"Their demands," Das said, "are too much."

The rat outside Veazie's window a few blocks away at 13th and Lombard was deployed by International Brotherhood of Electrical Workers Local 98, whose members added the earsplitting flourish of wailing baby cries.

IBEW picketers handed out leaflets decrying nonunion wages at the planned six-story expansion of Wesley Court apartments.

"Only a rat expects to get something for nothing," the leaflets read. People were urged to call contractor David Stafford, who owns City Center Construction.

IBEW business manager John "Johnny Doc" Dougherty would not comment about the rat or the screeching soundtrack. Stafford also declined to comment. But the rodent and the baby's keen vanished after Tuesday.

A representative of the local civic association, Judy Applebaum, said she had spoken separately to Dougherty and Councilman Mark Squilla earlier in the week, explaining that neighbors had gone crazy over the noisy nuisance.

"The rat," Applebaum noted, "was not my issue."

Scabby is no mere product of whimsy. The rat exists to fill a void created, essentially, by the law.

Decades ago, it was much easier for union members to picket at job sites where they were being excluded from work.

But unfavorable court rulings and other measures by developers in the 1980s eroded those picketing rights.

In response, unions turned to a right not easily curbed by judges: The First Amendment.

The silent rat would now do the talking, if not the walking.

"The rat is a form of protected speech," said William A. Harvey, managing partner of Klehr, Harrison, Harvey, Branzburg, a law firm that represents many local developers in disputes with labor.

"Unless the rat is blocking ingress or egress or is on private property, informational picketing - which is part of what the rat is - is permitted."

"I think," Harvey added, "that it remains an effective tool."

The word rat has long been favored in building trades circles over scab as the insult for those circumventing union-negotiated compensation, explained Patrick J. Eiding, a 40-year labor veteran who is president of the Philadelphia Council AFL-CIO and secretary-treasurer of the Philadelphia Building Trades Council.

"There's rats on that job," union members would say, or "That's a rat contractor," Eiding said.

In the last few years, both the New Jersey Supreme Court and a federal court judge in New York affirmed the rat as a form of free speech.

Eiding considers the rat an "innovation" among union tactics. He pointed to Local 98's recent use of the Rat-Mobile, and the "Fat Cat" inflatable feline preferred by the local Carpenters union. Both, he said, are effective if used sparingly and wisely.

"I'll probably be chastised by my brethren for this, but it's probably overused now," Eiding said of the gimmick.

And yet, he added, it is hard to argue that the rat or the fat cat do not make a lasting impression.

"It's still a good thing," Eiding said, because it still has the effect of getting people's attention."

215-854-2431 @Panaritism