The image appears to be in the shape of an angel, or a creature with wings. The image may be a hint to the Angel myth on the nearby Mount Chiliad. Others claim it serves as a marker that points in the "true" direction of Angels. Some people have claimed it is the Mothman or Pyramid Head. This could also be a tourist attraction as the town nearby is called Angel Pine, so this could be a symbol or namesake for the town. Some players can also see it having breasts, a possible reference to Adult Humor.
This myth may be the result of an optical illusion. It is mostly caused by two textures coming together to form an illusion. The rock shares the same two textures on the left and right side of the rock, and they are mirrored, creating a crude shape of an angel. This is a phenomenon known as pareidolia, where the human mind tries to find familiar shapes in random images.
Relation to Question Mark in the Woods
This myth is related to another myth called Question Mark in the Woods, which is a branch, which when viewed from particular points, makes a shape of a question mark. The relation is, that the head of the Angel on a rock, found in Back O' Beyond, points towards the direction, in which question mark is located indicating that the area lying between the two things possibly has some creature hidden. Or, there could be some other special secret being hidden in Back O' Beyond, as it is the place with the most occurrences of myths in San Andreas.