Scientists are testing a new form of liquid that's 'bulletproof'.
The liquid substance hardens as soon as a bullet hits it. This not only stops the bullet but absorbs a lot of the impact too.
It could be used to make liquid body armour, protecting the person wearing it.
Researchers think this substance could be used in many other applications, like protective sports equipment or as crash protection in car bumpers and road barriers.
Watch Hayley's report to see the extraordinary liquid in action.
Other footage courtesy of Blue Peter.