Apart from making our homes look a bit better on a budget, Ikea is known for their groundbreaking marketing strategies.

In 2016, they famously trolled Kanye after mentioning he was interested in collaboration with the Swedish company. They responded by producing a mock design of a bed featured in his Famous video. But nothing takes the piss as much as their latest campaign. The retailer has published a print advert in women’s magazine Amelia, which acts as a pregnancy test. The campaign invites readers to pee on the paper and — if the results are positive — you can purchase a crib for half price.

Created by agency Åkestam Holst with material technology company Mercene Labs, the ad features one of their cribs alongside a price tag — just like a standard ad would. However, when urine is added to the bottom of the page, similar to an at-home pregnancy test, the paper changes colour, but instead of showing two lines, it shows a new price which offers 50% off the crib.

“In order to make the interactive functions of this ad work in reality, we had to make several technical advancements,” Åkestam Holst tells AdWeek. “The pregnancy test strip was used as a starting point, which relies on antibodies that bind to the pregnancy hormone hCG, resulting in a colour change.

“For scaling up of this technique and adopting it to the physical format of a printed ad, Mercene Labs has used their experience in development of surface active materials for microfluidics and medical diagnostics. Careful selection of materials, together with a controlled capillary flow have been crucial for the success of this project. Technical advancements made during the work with this campaign have the potential to improve medical diagnostics.”

See how the ad works below: