See Robert Downey Jr. and Tom Holland Star in Astonishing Back To The Future Deepfake

In "Avengers: Endgame," Tony Stark scoffed at the rules of time travel introduced in "Back To The Future."

But that didn't stop Robert Downey Jr. and Tom Holland from appearing in the 1985 Robert Zemeckis classic in an eerily seamless deepfake making the viral rounds this week.

Created by Youtube user EZRyderX47, the amazing clip replaces Christopher Lloyd as Doc Brown with RDJ, while his young Avengers protege takes Michael J. Fox's place as Marty McFly.

The video has been viewed more than 3 million times.

Ironically, if Spider-Man hadn't been dusted by the snappening, the time heist may very well have been his idea instead, since Peter Parker came up with most of his best plans from classic films.

Deepfakes use a machine learning technique that identifies markers on an existing video of one person, and using a database of photographs and/or video of a second person, can render the latter's visage onto the former's.

The faked videos are swiftly becoming more and more convincing, and are already raising moral and legal questions regarding fake pornography and revenge porn, fake news and malicious hoaxes.

EZRyderX47 has created a number of impressive deepfake mash-ups over the past seven months, making Keanu Reeves Wolverine, Clint Eastwood Crocodile Dundee, and even reversing the Spider-Man/Back To The Future hash — albeit the Andrew Garfield one — by replacing him with Michael J. Fox.

Last month Facebook said it will begin banning deepfake videos it deems are purposely trying to mislead people, without disclosing they have been edited; satire and parody videos are not included.