http://www.telegraph.co.uk/news/worldnews/australiaandthepacific/australia/6442974/Tourists-in-Australia-warned-of-6m-monster-shark.html
Someone call Giant Octopus.
They need a few bottles of this:
http://www.krakenrum.com/
It could also be a killer whale, these are now known to attack and kill great white sharks.
Thats another reason to add to my list of reasons not to live in Austrialia.