Answer:
An iron horse with a flaxen tail. The faster the horse runs, the shorter his tail becomes.
A precious fluid, thicker than water.
When you stop and look, you can always see me. If you try to touch, you cannot feel me. I cannot move, but as you near me, I will move away from you.
You will find me with four legs, but no hair. People ride me for hours, but I don't go anywhere without needing to be tugged. Jerked or turned on, I always manage to be ready for work.
Useful tool for who in darkness dwell. Within you, corrupting like a deadly spell.
A doctor might remove one from the neck of a Dracula victim.