Haze panthers self buff with invis:
A haze panther begins casting Air Elemental Invisibility.
a haze panther fades away.
And they have an annoying habit of porting out of range when you try to kill them. Not sure why a shadowstep spell makes them also gate, but that's what's happening. Best to smite them before they even see you.
A haze panther begins casting Scareling Step.
A haze panther Gates.