Good Riddles

Question: One stroke is not enough to deal damage but combined with many strokes, I am able to deal mass damage. What am I?

Question: A guy writes in his journal. He writes "Hey, journal, today I... 'Dinner is ready!' Is what his wife said." But the guy had no wife. How is this possible?

Question: can you make an equation by using only the no.-4,4,4,4 whose answer will be 20.

Question: What wears a black suit and watches while stalking?

Question: I'm just a lot of nothing but I'm every were... what am I?