Answer:
I go through a door but never go in and never come out.
I am a type of cheese made backwards
I walk on 4 legs in the morning, 2 legs at noon, and 3 legs at night. What am I?
I am as hard as metal, yet as flimsy as glass. I shine like a star, yet I am only a rock. What am I?
You can never eat me for breakfast or lunch. What am I?
When is it bad luck to see a black cat?