Traveling in Australia, I met an old Gunwinggu man in the Northern Territory who told a strange tale. He reported seeing "little yellow people riding a dead man" some years ago. After weeks of fruitless searching, I finally did get a brief glimpse of the thing he described.
I was camped in the Simpson desert. Just after dawn, I woke to the sound of something rummaging through my provisions -- and there it was.
The creature looks much like a bleached human skeleton. One could easily believe that the emaciated thing is nothing but bones -- but it is covered by skin. It is headless, and moves on all fours. It doesn't have hands or feet, but rather insect-like points at the ends of its limbs. I was unable to see any sensory organs.
The ribcage is not closed; it hangs wide open, and is perhaps three feet wide. A large green-black sack hangs from the interior. I presume this is where the vital organs reside. It is also where the Yellow Riders dangle.
The Yellow Riders are small almost-spherical creatures with bright green eyes. There were perhaps fifteen attached to the skeletal being's ventral sack by sinewy roots.
As I came out of my pup tent, the Riders seemed to take notice -- making squeaky sounds and bobbing up and down. Their white mount took off at a gallop.
I leapt into my jeep and chased them across a field of cracking dried red mud... But the creatures quickly outpaced me -- meaning that the white thing can run at speeds in excess of 80 miles per hour.
I have no explanation for what this thing that I encountered might be. It seems likely that the Yellow Riders have a symbiotic relationship with the galloping creature... All I can say for certain, though, is that it likes peanut butter.