Answer:
A huge mythical animal said to resemble a whale.
I live in the ocean but I am not a fish. I have eight arms and can change colors quickly. What am I?
Face with a tree, skin like the sea. A great beast I am. Yet vermin frightens me.
The ninja turtles call this place home, as do mythical alligators.
When I'm metal or wood, I help you get home. When I'm flesh and I'm blood. In the darkness I roam.
What is often on the ground getting stepped on by others, but you donโt have to wash it because it never get dirty, in fact you couldnโt wash it even if you tried?