Satanas
In the first Technicolor sci-fi movie, Satanos becomes the precursor of all cats who appear gigantic to miniaturised humans.
Although megalomaniac Dr. Alexander Thorkel (Albert Dekker) does very homicidal things, the story is largely comical with plucked violin strings in the background music which are reminiscent of cartoons from the same period.
Apart from an obvious reinterpretation of the Homeric story of Polyphemus and Odysseus at the climax, the movie is also famous for the amusing scene where Satanos tries to catch the tiny scientists before being chased away by a dog. It's just like something out of "Tom and Jerry" but with live action, rear projection and giant cacti.
Blink and you'll miss it, but there's even a real big cat who is almost eclipsed by a flash of lightning during the brief tropical storm which follows.
In the epilogue, set months later with everyone back to normal size and in civilisation, Steve Baker (Victor Kilian), the formerly terrified but pushy mule trader, enjoys yelling "Scat!" at a completely innocent cat just to make himself feel big again.