The X-files 1x10 -

An invisible entity stalks the woods, killing those who come too close.

: Fans often cite this as the episode where the "Core Mythology" really began to take shape, moving beyond "Monster of the Week" filler. The X-Files 1x10

Mulder is captured and meets , a frantic NICAP member and recurring UFO abductee. An invisible entity stalks the woods, killing those