Question: What is the monster that has been attacking ships?
Answer: The monster is a giant Narwhal, that is somehow electric.

Question: What makes the Narwhal electric?
Answer: The Narwhal is actually a giant submarine.

Question: Who is piloting the submarine?
Answer: The submarine is pilotted by Captain Nemo, and the submarine is called the Nautilus.

Question: Why does Captain Nemo attack ships?
Answer: Because the people on board the ships always attack his submarine, thinking that it is a monster.

Question: What happened to Captain Nemo that makes him hate man-kind, and live alone with his crew?