In SUSPIRIA, Italian filmmaker Dario Argento (DEEP RED) introduced us to a German dance academy residing in an elaborate mansion that was really a front for a coven of witches. He followed up with INFERNO, which told us that there were three such structures, designed by an architect named Varelli, which housed the Three Mothers, ancient evil beings who sewed death and destruction upon mankind: the Mother of Sighs (from SUSPIRIA), the Mother of Darkness (who presides over most of the events in INFERNO), and the Mother of Tears (who presumably is to be the subject of an as yet unfilmed story).
Although the Mother of Tears never got her own film, a mysterious, beautiful woman shows up early in INFERNO, gazing portentously at the hero. Although she is never identified, most viewers assumed she was the Mother of Tears, making a cameo appearance, and Argento himself eventually confirmed this.
As you can see, she is accompanied by a familiar: a white cat, not unlike the one that Blofeld used to pet in the James Bond films. This seems to imply that felines are in some way aligned with the Three Mothers -- an implication that plays a part in a major set piece later in the film.
At one point, a crippled old seller of rare books, named Kazanian stuffs a bunch of cats into a bag and takes them out into New York's Central Park, where he drowns them. As he finishes, a mysterious eclipse occurs, signaling the arrival of the forces of darkness. Kazanian drops his crutch and falls into the water. In a rare show of interspecies solidarity, the local rats avenge the death of the felines by attacking Kazanian. In a genuinely repulsive scene, the rodents crawl all over him, biting at his skin. His panicked cries of "Help! They're eating me alive!" catch the ear of someone working at a local hot dog stand, who drops what he's doing and runs, apparently to the rescue. But the Three Mothers are not so easily thwarted...
You'll have to rent the movie to see what happens. It is highly recommend, especially if you like strong visuals and atmosphere, mixed with intensely gorey set pieces. Argento is a big influence on later filmmakers. Most recently, the South Korean import NIGHTMARE contained several Argento-like moments.