What Am I Riddles

Question: When I come in, someone else leaves, I know everyone, yet no one knows me. I'll meet you all only once in your life, Causing mayhem and mischief and sorrowful strife. What am I?

Question: With pointed fangs I sit and wait, with piercing force I serve out fate. Grabbing bloodless victims, proclaiming my might; physically joining with a single bite.What am I?

Question: There's a B in my hand. So what's in my eye?

Question: Look at my face, I am somebody. look at my back, i am nobody. What am I?

Question: This is a fruit. You cross off the first letter it is a crime. Cross of the second letter its an animal. Cross off the next two letters it is a vowel. What is it?