Answer:
I shift around though always slowly. I never move more than a few inches at a time. A large movement by me can kill many people. I am huge yet unseen by humans.
What comes once in a year twice in a week but never in a day?
I love spinach.
My tail is long, my coat is brown. I like the country, I like the town. I can live in a house or live in a shed, and I come out to play when you are in bed. What am I?
What kind of dog keeps the best time?
I go in hard, come out soft. Blow me hard and I'll make a pop. What am I?