Two questions come to mind when using this monster's Spectral Strangulation ability:
1) What is the range of this ability? This is its primary attack form but the text only says the creature needs to be on the "same plane" to use it. The creature has lifesense so the maximum range would be 60 feet but what's the minimum? I'm using Close range as per magic spells.
2) If a target fails the initial Spectral Strangulation Will save but passes the second Fort save, the text says "the victim acts as if affected by a fear spell for 1d4 rounds." Does that mean panicked for 1d4 rounds or does that mean make a Will save with failure meaning panicked and success meaning shaken?
1) You would need line of effect/sight to the creature, RAW.
2) I would rule as if the fear spell weren't saved successfully, so panicked.
The book is from a 3PP so I'm just trying to work with RAW here, the question might be better off in the "compatible" forum.