Fluke

Weighting over ten feet tall
Feet of clay, head of gold
Middle made of cannon balls
Rumour has is swallowed whole
Mineral, without a soul
That's the story being told
The estimated, undefeted
Champeen of the world
Big yet unfamiliar
Think bigger than the biggest bar
Think big, that's only half as large
Bigger, better, twice as hard
Outsized, extra large