There is no question there are rocks that have very odd shapes, even some in Arizona that seem to stand on end, but you don't see these rocks rolling
around.
From the length of the shadow, the rock (if it is a rock) would be long and slender, not round. If it were round, it would roll, no question. If it is
long and more slender, oblong shape, it would not roll, unless it was laying on its sides, which it clearly is not. If by some strange occurrence this
oblong "rock" were to roll down the hill, it would almost certainly not hop up and down, but roll "head over heels" style, leaving large flat
imprints, then short "end" imprints, then repeat the pattern. The pattern visible does not show this action happening.
Strange!