Where did the meme G major come from and what does it have to do with Giygas?

The origins of the "G-Major" meme appear to have first started on YouTube and have remained quite popular to his day, due to its "scary" and "creepy" sound effects. The earliest know video that utilizes G-major is PanicBomber's Scaryroll and the view count has nearly reached one million views.

As for the relationship between G-major and Giygas, I assume that both subjects fascinate fans due to its "Horror" elements that is entertaining for some people.

Citations:

KnowYourMeme.com