Answer:
I cause involuntary movements in your vehicle
First you see me in the grass dressed in yellow gay; next I am in dainty white, then I fly away. What am I?
I have thirteen hearts but no body or soul.
People buy me to eat but never eat me. What am I?
A dagger thrust at my own heart dictates the way I'm swayed. Left I stand and right I yield to the twisting of the blade. What am I?
A doctor might remove one from the neck of a Dracula victim.