Strange sea creature

When we first got here and walked at low tide we spotted one of these strange creatures, when I asked around no one had seen anything like it, a sea snake with a frilled neck sounded pretty unlikely. Nothing came up on google and I had no picture to post on the forums.

We just spotted another and got a photo, I put it up on a snake and python forum and some brilliant mind has identified it for us! Apparently it is known in these northern waters and many countries across the tropics see fishbase.