Weight in my belly trees on my back riddle

Question: Weight in my stomach,trees on my back,nails in my ribs,it's feet I lack.What am I?

Question: What fish only swims at night?

Question: What do you call a mad elephant?

Question: What kind of mouse does not eat, drink or even walk?

Question: What has a bed that you can't sleep in?

Question: Where do all the letters sleep?