We've had the thigh gap, the bikini bridge and the ridiculous A4 waist challenge, and now there's a new body-shaming trend to make us feel bad about ourselves - the ab crack.
An ab-crack is a curve that extends down the centre of the stomach and can only be achieved if you've spent lots of time at the gym.
Still confused? Here's a picture of Blurred Lines and Gone Girl star Emily Ratajkowski looking smoking hot in a bikini.
Get it?