Lightning

Lightning is very common during Halloween(after and on Halloween Party 2008).

Origin
Lightning was expected before the Halloween Party 2008 arrived. Gary the Gadget Guy says that a lightning storm will hit the island just in time for Halloween. During the event, Lightning flashing from outside the Dojo are revealing Ninja Shadows. After the event, The last lightning struck the Dojo, which revealed it's exterior. Since then, Lightning occurs every Halloween. Clicking on the sky will result in the strike of lightning.

Trivia

 * The biggest lightning is recorded on high places where the clouds are closer.