It's Halloween costume shopping season, and a familiar dress and viral phenomenon is on sale as a costume at an online retail store. Back in February, a post of "the dress," which originally appeared on Tumblr, caused a meltdown among social media users. People were divided as to the actual color of the dress. Some said they saw a blue and black combination, while others said it was white and gold.

The dress debate got so heated that science experts tried to offer a correct answer. "What's happening here is your visual system is looking at this thing, and you're trying to discount the chromatic bias of the daylight axis," said neuroscientist Bevil Conway, according to Wired. "So people either discount the blue side, in which case they end up seeing white and gold, or discount the gold side, in which case they end up with blue and black."

Now, the famous dress has become a suggested Halloween costume. Called the "What is the Color?" Dress Costume, it is retailing for $46.95 at Yandy. To avoid any more confusion, the costume has both combinations of shades in one piece - blue/black on one side and white/gold on the other side.

Meanwhile, the actual dress is still being sold at Roman Originals, where it comes in many colors, including a separate blue and white dress.

A version of the blue/black combination is also available at Amazon Fashion.