Board Thread:Ninjago Wiki News/@comment-26739460-20150722145741/@comment-25374175-20150807020727

This is a thinker. On one side, Cole being a solid makes his life a little safer around water (this might be a huge threat considering Nya possess the element of water). On the other hand, being a gas/ghost allows the Earth Ninja to possess things freely at his will, making things less harder and easier for nearly impossible missions.

This has a lot of pros and cons like you stated on the top of the page though water doesn’t exactly kill him—after the ghost corrupted the Samurai X mech, Nya summoned rain in accident though was causing the dead creatures pain but was not sending them back to the Cursed Realm; this may apply for Cole too.