What is Gallon smashing?

Gallon smashing is the act of spilling a gallon of liquid , usually by breaking its container , in a manner that appears to be accidental. The act often involves throwing a gallon of milk onto a grocery store aisle, then falling, getting members of the public to help the 'smasher' get up, and sometimes having difficulty returning to a standing position. The act is generally done as a "prank" meant to share on the internet, and so typically recorded on camera.