The original, from TankerEnemy.com. It is just a USAF KC-10 Extender flying through patches of warm moist air, forming an aerodynamic contrail off the leading edge of the wing. It was filmed by the flight engineer from the trailing KC-10, since they were flying in formation.
TankerEnemy takes their time to circle the flap hinges which they perceive to be spray nozzles, spraying deadly chemicals into the skies. The replies for a lot of these videos gets pretty violent, with people advocating physical harm, even death to pilots, going as far as to urge one another to purchase Stinger missiles and SAM's to shoot airliners down.
It became such a joke in the KC-10 community, that the FE that filmed it, rereleased the video with fake voiceovers, pretending they were actually "spraying a chemtrail". He even went on TankerEnemy to ridicule them and tell them it was a spoof.