Definitely a chemtrail, specifically phenolphthalein.
They were most likely testing the pH effects of their prior chemtrail operation (those fake clouds). The Pink color indicates that the area is basic as opposed to the atmospheres usual acidic state, under acidic conditions it would be colorless.
Edit: down votes already rolling in from the group of gangstalkers they have on my case smh. I will not be silenced!
spoiler
/s
That's what makes it good imo.