By choosing Njord as a minor god while playing as the Norse in an island scenario, you will get the Kraken unit, which is a large octopus that instantly kills any water unit by pulling it underwater with it's tentacles. When your opponent loads up a transport ship with his expensive army, have the Kraken sink it and kill their entire army before they even set foot on your shores. This is even easier when playing against the computer, because the AI picks a route for the transport ship and sticks with it.