A generally large, overweight, or obese person usually compared to a whale that has been harpooned by a ship and got away. Basically entailing that the person is as big as a whale, and has scars on their back just like a once harpooned whale.
There are many different breeds that include:
Holy shit Marv! Did you see the size of that scarback!
That scarback had the largest fupa i have ever seen!