I had no idea what the rat was. It was only later when I did my research that I discovered--here at Business Insider, here at Mental Floss, and, most authoritatively, here at Wikipedia--that these ugly inflatable rats are used by American unions to protest employers that make use of non-union workers.
This is one minor element of several illustrating for me how Americans can be so much more confrontational than Canadians. (This can be a good thing; this can be a good thing here.) Does anyone know if Scabby the Rat has ever appeared in Canada?