It's no secret that sisters are at each other's throats throughout their lifetimes, fighting over anything and everything, whether it's a stolen top or missing hair straighteners.
But it seems two identical twin sisters in China couldn't wait to be born to have their first fight - so had it out in the womb!
The siblings were spotted having an onscreen row after their mother went to the doctors for an ultrasound. The video, filmed by their father, seemingly shows the pair kicking and hitting each other at an antenatal check-up late last year in the city of Yinchuan, the capital of the Ningxia Hui Autonomous Region in China.
Their spat quickly went viral, after the 28-year-old dad uploaded the ultrasound footage to short video app Douyin, gaining more than 2.5 million likes and 80,000 comments. It has also been widely shared by Chinese news outlets, including China Daily.Is this ultrasound a sign of things to come?
Their father, Mr Tao, told Chinese news outlet The Paper that he had found it funny to see his two kids seemingly "boxing with each other for a few rounds" before they were born, adding that he hadn't expected his daughters "to be internet stars before being born".
It was a dramatic pregnancy, even without the twins exchanging blows in their mother's belly. According to reports, their mother went through one of the highest risk twin pregnancies possible.
This is due to the two babies sharing the same amniotic sac as well as placenta inside their mother, something known as monochorionic monoamniotic twins or Mo-Mo twins.
Monoamniotic twins - a rare thing that occurs in approximately 1 in 35,000 to 1 in 60,000 pregnancies, according to TwinsUK - develop when an embryo does not split until after the formation of the amniotic sac, at about nine to 13 days after fertilization.
The biggest risk with this type of pregnancy is that the umbilical cords - each twin has one - will get tangled and knotted, resulting in impaired blood flow to one or both of the babies.
There are differing survival estimates, with some reports claiming it is as high as 81 per cent to 95 per cent in 2009 (with aggressive fetal monitoring), but others previously stating it is as low as 50 per cent to 60 per cent.
According to the Yangzhou Evening News, doctors at the General Hospital of Ningxia Medical University planned emergency surgery after nurses saw one of the twins' heart rate had suddenly dropped.
During the operation, they found a large portion of their umbilical cords had got tangled, but thankfully, the two sisters beat the odds (and didn't beat each other up too much in the womb), coming out completely healthy after their mother had a C-section. They are nicknamed 'Cherry' and 'Strawberry'.
Deputy director from the hospital He Lin said: "The babies have been born safe and sound. It's their parents' fortune as well as my fortune. They are the first pair of Mo-Mo twins our hospital has successfully delivered."
May Cherry and Strawberry have many more years of bickering to come!