Elon Musk has once again warned about the dangers of unchecked artificial intelligence, this time in response to a viral video of a robot doing amazing acrobatic feats.

Twitter user Alex Medina, a designer for Vox Media, posted a clip of a Boston Dynamics humanoid robot called Atlas doing a backflip with the short caption: "we dead."

In reply, Musk wrote, "This is nothing. In a few years, that bot will move so fast you'll need a strobe light to see it. Sweet dreams."

He then went on to elaborate on his comment in a follow-up tweet.

"Got to regulate AI/robotics like we do food, drugs, aircraft & cars. Public risks require public oversight. Getting rid of the FAA wdn’t [sic] make flying safer. They’re there for good reason."

This is just the latest warning from Musk about robots, which he considers "humanity's biggest existential threat." At a talk at the National Governors Association meeting in July, Musk said lawmakers need to start regulating robots before they start "killing people." He also signed on to a 2015 letter by technology luminaries urging the United Nations to ban killer robots. [History of A.I.: Artificial Intelligence (Infographic)]

Elon Musk's fear of robots is shared by many brilliant scientists. Stephen Hawking has also warned on numerous occasions that artificial intelligence could spell the end of the human race. Billionaire and software icon Bill Gates has said he doesn't understand how some people aren't concerned about the potential threat of A.I.

The robot shown in the video probably doesn't pose any threat to humanity — yet. It's still not as nimble and versatile as an ordinary human, and according to the Defense Advanced Research Projects Agency (DARPA), Atlas isn't meant to be a killer robot. Instead, it's designed as a disaster robot that could do things like search for humans in rubble, where it would be too hazardous to send human beings.

Originally published on Live Science.