Made me lol
Animation-
It was basic, but good enough for this flash. When the seven yells and eats 9, 9's expression should change to one fear, and it should shout as well after the roar.
Sound-
The steps don't sync with the footsteps, other than that, it's good (especially the roar). You might have wanted to put calming music at first then added a sound that surprises the audience when 7 eats nine.
Content:
Can't say too much for originality, but it does get straight to the point. You need a replay button though, and maybe a scene with six in the back ground with an expression like 0.0 or 0o0.