Origin

"Hell Valley Sky Trees" is a Super Mario creepypasta originating in the game Super Mario Galaxy 2 for the Nintendo console Wii. Less than a month after the game was released, an anonymous tip saying that in the level (which in the game are referred to as galaxies) Shiverburn Galaxy, when you reached a certain spot, you could go into first person mode and see three figures on the edge of the map prompted an article on GoNintendo titled "The mysterious figures of Shiverburn Galaxy". A few weeks later, a creepypasta titled Beyond Hell Valley was posted to the Creepypasta Wikia, including images taken from the article.

Speculation on the Internet

Across the forums in the Internet, there has been much speculation over what these figures are, since Nintendo has yet to say anything at all about these shadowy figures. Among the speculators, a large number of them can be found on this thread on the NintendoLife Forums.

"BEYOND HELL VALLEY"

Eventually, it was determined what the name of the creatures were. By hacking the game and accessing the game files, one can see that the figures are actually part of the skybox, the map surrounding them is under the file title "Beyond Hell Valley" (NOTE: this is translated from Japanese, due to the fact that the game was made by Nintendo ^TM, a Japanese company) and they themselves are called "Hell Valley Sky Tree(s)", though they look nothing like trees. No character in the game mentions their existence. But when the player goes into the first person view, the figures are always there, as if they were watching Mario.

Extra Links
Link to Cracked Article see #8

[still researching help is greatly appreciated]