A stock market trader bet against a high profile company. Later, a video of the Chief Exec admitting a cocaine addiction while describing his company's products as substandard to impress a young woman - went viral. The stock price cratered, and while the news media were scrambling to verify the story, the trader exited his position and did quite well out of it. 

The video of the Chief Exec was convincingly faked using software freely available on the internet, but by the time this was clear - it was too late.

As far as I know, this story isn't true - but if you havn't seen any of the deepfake videos doing the rounds, you know that this story of stock market manipulation is the very least we have to fear.

Deepfake videos are just getting started. If you look really carefully you can see they are indeed faked - but you do have to look very carefully, in time - they will get even better. 

People caught red handed will be able to claim footage is doctored, people innocent of all wrongdoing can have their lives decimated by bad actors. 

I can see brands using this for fun, dictators using it for ill, and Twitter filling up with ever more outrageous memes. This stuff is just going to get woven into the fabric of our digital lives, and there is not much we can do about it.