Fish

Googley Doodley Doo
Googley Doodley Doo

What began
  as a simple fish
     became a big fail,
  so it morphed into
     an almost-whale,
  until a bird emerged,
     feathers and tail,
        a disproportioned,
             un
                    balanced
                         pale comparison,
     yet on some scale
        appears similar
             to the creature
                it resembles,
                     apart from the details.