Ninjas on Club Penguin
UPDATE: There have been so many sightings of ninjas on Club Penguin that I made a page to show them all here: Club Penguin Ninjas.
The rumors of ninjas on Club Penguin are starting to come true. There is a big lightning storm on Club Penguin this week and during the flashes of lightning you can see ninjas appear in the Dojo.
Go to the dojo and wait for a big lightning strike. You will see a brief flash of the shadow of a ninja up in the windows. Look quickly because he will disappear in a flash.