Final answer:
The innovative cartoon short mentioned is 'A Boy and His Atom,' a film created by IBM Research using a scanning tunneling microscope to animate molecules. It's a unique narrative about a friendship between a boy and an atom, diverging from traditional cartoons by focusing on scientific illustration and a mood piece.
Step-by-step explanation:
A Boy And His Atom: The World's Smallest Movie
The cartoon short in question is most likely A Boy and His Atom, which was released by IBM Research in 2012. This innovative film is often celebrated for its groundbreaking approach to animation. Instead of relying on traditional narratives or characters, it focuses on the story of a boy and a single atom forming a friendship. Remarkably, the animation was created by physically moving carbon monoxide molecules with a scanning tunneling microscope, magnifying them 100 million times to create visible structures that were captured frame by frame, thereby creating the film. Contrasting the typical cartoon for entertainment, this piece of art stands out as a mood piece that conforms to a music track, rather than serving as a vehicle for gags.
Although the question hints at 'the best short cartoon of all time' which could be subjective, the information provided points clearly to A Boy and His Atom.