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 can one catch that is not thrown?
I can be long or short. I can be grown or bought. I can be painted or left bare. My tip can be round or square. (one word)
I am used when you jump off a bridge for fun.
I am the only thing that place today before yesterday. (one word)
Runs over fields and woods all day. Under the bed at night sits not alone, With long tongue hanging out, Resting at your feet until we go for a walk