Smoke; carbon dioxide is invisible. In fact, it is not (carbon dioxide) smoke, but (water) mist. When carbon dioxide changes from solid to gas, it absorbs a lot of heat, so that the temperature of the surrounding air drops quickly, and the air temperature drops. Its solubility in water becomes smaller, and water vapor condenses, so the surrounding water vapor becomes small droplets, which are mists. This is the same as summer popsicles emitting white smoke. They are all small water droplets, not gaseous other substances. That is, we see white mist instead of white smoke. Dry ice entering the water is much cooler than water. So it is equivalent to heating dry ice, which absorbs heat and sublimates, which lowers the temperature of the water and even freezes it.