Good Riddles

Question: In 2000, a 40-year-old doctor told his son that, when he was a little boy, he decided to be a doctor after seeing on the internet a heart transplant being performed on a puppy with a defective heart so that the puppy could live a normal life. The boy then thought about being a doctor too someday so that he could help people in a similar way. What's wrong in this story?

Question: What has 18 legs and catches flies?

Question: What do you call a king who is 12 inches tall?

Question: What did the banana say to the elephant?

Question: Before your choose the witching hour, take care to dream the tallest tower. Than careful before you leave too soon--behold the dark and hollow moon. What's the number? (This Riddle is from the Eye of Minds, by James Dashner.)