Online advertisements of women wearing onesies that reveal their bottoms has sparked confusion among those finding them.
According to the BBC, ads for the "plain functional buttoned adult pyjamas" promoted by Chinese brands IVRose and ChicMe began popping up across websites last week.
Many internet users who have spotted the ads have been left wondering why the 'butt-less' pyjamas were promoted to them, and why they were 'butt-less' to begin with.
The two brands promoting the product share contact details and seem to be owned by the same Chinese firm, Shanghai Lishang Information Technology Co Ltd.
The firm's website is also owned by the same company, Alkmand Estate, which runs several clothing retailers, all selling the rather risque sleepwear.
Planning director at marketing agency Digital Whiskey Mat Morrison told BBC that Chinese advertisers are known for using lewd wardrobe-malfunction style ads as a way to grab people's attention.
"They've created a tantalising advertisement that is just about 'clean' enough to pass publishers' propriety rules, but salacious enough to capture audience interest."
Morrison said the reason so many people were seeing the viral ad might be because it was targeted towards a large group such as a whole gender or age group rather than a smaller, more specific audience.
He said the reason for the ad may be so Chinese retailers can bypass sites such as Amazon and have consumers buy directly from their sites, increasing margin and profit or to track clicks and target those interested again in the future.