A photograph putatively showing a tornado sucking up the colors of an adjacent rainbow has been circulating around the Internet since at least as far back as 2012:
While the image is frequently shared along with a statement declaring it to be authentic, the picture is actually a piece of digital artwork created by Corey Cowan:
It is a composite of three images. Two rainbows and a tornado. The original tornado image is this, which I stretched a bit and masked.
Tornadoes may be incredibly powerful, but they do not affect light in the manner depicted in this viral photograph. In 2004, storm chaser Eric Nguyen captured the way a rainbow actually appears during a tornado:
While the above-referenced photograph also looks manipulated (this time it appears as if the rainbow is sucking up the tornado), the presence of the rainbow was merely a coincidence:
Storm chaser Eric Nguyen photographed this budding twister in a different light, the light of a rainbow. Pictured above, a white tornado cloud descends from a dark storm cloud. The sun, peeking through a clear patch of sky to the left, illuminates some buildings in the foreground. Sunlight reflects off raindrops to form a rainbow. By coincidence, the tornado appears to end right over the rainbow.