In case you've been living under a rock, it's where everyone in the room stands still while the camera records everyone perfectly still.
Lots of people have done it. It's cute. It's hip. But when it ends, everyone gets a good laugh and that's that.
Not for one couple in The Woodlands.
When Sue Merino and Jamie Ferrini went to Thanksgiving dinner, they thought they'd do the Mannequin Challenge. Merino and Ferrini were standing close. Merino had a glass of wine. Ferrini had an engagement ring.
He taps her on the back, she turns and he's on one knee.
The family cheers as she nods her head.
The post was uploaded to Facebook, where it has nearly 12,000 shares and 5.5 million views.