We've had the ice bucket challenge, the cinnamon challenge, the Kylie Jenner lip challenge and the mannequin challenge.
As these blink-and-you'll-miss-them social media trends grow ever more ridiculous, the internet has hit upon its most risque craze yet - the one-finger selfie challenge.
The female photographer stands in front of a mirror and snaps herself naked except for a strategically placed finger that covers her genitals and breasts when reflected.
The concept originated with an illustration by Japanese anime artist Sky-FreeDom, which shows a naked girl using one finger reflected in a mirror to cover her breasts and private parts.
