The Gorilla in a Tutu Principle or, Pecan Pie at Minnie and Earl's
Novella 20,795 words Recommended by 4 award/anthology sources
A young man working on the moon during a construction boom keeps seeing two men doing crazy things in the middle of nowhere. Men who leave no trace and whom no one else can see.
Quasar links out; the story lives on Analog, where the author gets the click.