Answer:
I have two bodies joined together as one. When standing still I run and run.
I wiggle and cannot see; sometimes underground and sometimes on a tree. I really don't want to be on a hook and I become a person when combined with “book”.
What has many keys but can't open a single lock?
I'm tall I'm round and hollow Seems to get chewed a bit But you'll rarely see me unless the other end is lit.
I have a strong affection for belly buttons.
When is it bad luck to see a black cat?