Riddles (HARD)

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Across
  1. 2. What animal would you get crossed a duck, a beaver, and an otter?
  2. 4. I can flutter and take your breath away.
  3. 6. It has a long neck, A name of a bird, Feeds on cargo of ships, It's not alive, What is it?
  4. 8. I stopped you would be sure to lose.
Down
  1. 1. am I?
  2. 3. With pointed fangs I sit and wait; with piercing force I crunch out fate; grabbing victims, proclaiming might; physically joining with a single bite. What am I?
  3. 5. A man in a car saw a Golden Door, Silver Door and a Bronze Door. What door did he open first? Hint (Don't put the word door in your answer)
  4. 6. The person who makes it has no need of it; the person who buys it has no use for it. The person who uses it can neither see nor feel it. What is it?
  5. 7. day and night, I am with you.