cat ice
A thin (half inch or less) sheet of ice from which the liquid water underneath has receded or drained off, leaving it supported only at its edges. So named because it might support the weight of a light-footed cat, but no more. Typically found on urban sidewalks or gutters where the surface is uneven and sunlight is hit-and-miss. Occasionally found on natural bodies of water.
Joe: This sidewalk is covered in ice. Maybe we should go around it so we don't slip and fall.
Mike: Nah, look closer, it's cat ice. It'll break into tiny pieces as soon as we step on it and we won't slip.
Mike: Nah, look closer, it's cat ice. It'll break into tiny pieces as soon as we step on it and we won't slip.