I found a picture of the first thing that came to mind when I saw 'worst cereal' All Bran.
Second place goes to Fruity Pebbles. Not because it tastes bad, but because it literally causes instant colon cancer.
It's too bad the posts don't merge.
Also, balls so big the jester couldn't juggle them.
They bounce and roll leaving chaos in their wake.
Too big for the circus.
Too wild for the stage.