Blinking Spirit casts Blink (shadowstep).
Casts Flash of Light (1-tick mez everyone on its hatelist and deaggro/forget you).
Placeholders are a tomb shade in the graveyard.
Placeholders are indifferent, but Blinking Spirit is KoS.
Placeholders are invisible with SoS, but Blinking Spirit is visible.
To view or track the shades which are placeholders you need WIZ MAG 77 Aspect of Zomm, RNG 76 Skylight Sagacity, DRU 77 Sharp Eyes or 87 Eyes of the Winter Hawk. Or use an AE to get aggro. They are social with each other.