NEW YORK (CBSNewYork) – For years giant inflatable rats have been familiar to New Yorkers walking past countless union protests, but now their reign of shame may be over.

In documents filed by the National Labor Relations Board, a claim has been made that the labor movement’s use of inflatable balloons is illegal.

The rat balloon known as “Scabby” – with blood-red eyes, filthy grasping claws and “scabs” on its bloated belly – has been an icon around the city, often placed outside work contract sites to shame owners and spotlight grievances.

Last year, an advice memorandum by the Trump-appointed general counsel at the National Labor Relations Board declared inflatables similar to Scabby should be illegal for unions to use in protest of unfair employment practices.

READ: United States Government National Labor Relations Board Advice Memorandum

In the memo, a case involving “a large, inflatable cat clutching a construction worker by the neck” in Chicago was blamed for being “coercive” and “unlawful” at the site.

The memo’s author said the balloon was a “symbolic, confrontational barrier” which caused at least two workers to turn away from the worksite.

An inflatable protest rat is blown up and laid out to dry at UA Plumbers Local 14 Training Center after rains and the cresting of nearby waters flooded the facility on Aug. 29, 2011, in Lodi, New Jersey. (credit: Michael Loccisano/Getty Images)

The popular “Scabby the rat” design traces back to at least 1989 when the International Union of Operating Engineers Local 150 used it to promote their grievances in Illinois. These days the rat is even active on social media.

The recent Chicago case is not the first time the future of the inflatables has been debated. In 2013, a union blogger quoted an AFL-CIO Building and Construction Trades Department official as saying the rat “symbolizes intimidation tactics of 30 years ago. We want to engage owners re: our value proposition not threaten them.”

If all this ire toward “Scabby” holds up, a case in New York City could spell its legal doom.

Reports on Gothamist say in June the owner of the ShopRite on Hylan Boulevard in Staten Island filed a complaint with the NLRB when two “Scabby” rats inflated outside the supermarket.

If the case goes before an NLRB judge, the general counsel’s memo could lead to a final ruling banning such balloons at demonstration sites, and “Scabby” could be deflated for good.