Answer:
I have an eye but cannot see, You'll head inside when you see me.
When the son of the water returns to the parent, it dies. What is it?
I build up castles. I tear down mountains. I make some men blind. I help others to see.
What moves without seeing and cries without eyes?
Long and slinky like a trout, never sings till it's guts come out.
People take me on walks and I run and have fun. What am I?