Spherical UFO With Vapor Camouflage Photographed in Japan

The best way to hide something is (arguably) to leave it in plain sight. And what sight would look as plain as clouds in our sky? If aliens are trying to hide their presence while studying us, why waste the energy to turn their ships invisible when they could just extract moisture from the air and surround their space ship with a thick layer of fog? If they did this, wouldn’t a spherical UFO look like the cloud in the photos below?

Numerous close encounters mention the apparition of unnatural fog at times and temperatures where it shouldn’t be able to form. Clouds and fog are essentially water vapor and it wouldn’t be too hard for a UFO to use the heat from its engines and the gravitational pull they exert to attract and heat water molecules until a gaseous shroud is in place to keep them hidden from watchful eyes.

Is this phenomenon behind the recently-photographed, extremely conspicuous cloud that appeared over Japan? Is there a spherical UFO behind all that fluffy white?