Close. Everyone forgets that a neutron star is held together by gravity. Take a bit away and that bit will fall apart. Rapidly. Very, very, very rapidly. Like significant fraction of c rapidly. Imagine Mt. Everest suddenly flying apart at a significant fraction of c.
You mean like....ALL life on Earth? From a single teaspoon full? I doubt it. Would it kill the drunk camper who picks it up and decides to use it to keep his sleeping bag warm? Maybe.