Answer:
I am a nut with a hole
I am the ultimate killing machine used not once but TWICE I can be made by humans.
The Titanic is still here.
Only one color, but not one size. Stuck at the bottom, yet easily flies. Present in sun, but not in rain; doing no harm, and feeling no pain. What am I?
My first is a heir; My second's a snare; my whole is the offspring of fancy; which I sent out of play upon Valentine's day As a token of love to my Nancy.
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?