I know this will probably come as a surprise, but I'm actually leaning toward straight-ahead monster with PLAs as well!
The spirit can also attempt to drive a character mad. Whenever the ghost successfully uses its telepathic probe it can force a character to look inside its demented mind. The character must then make a madness check. The psionic spirit can cause madness in a character of any class, not just psionicists.
That makes good sense. We might blend in an alien mind-like retributive effect as well for those who willingly try to probe its mind.
It should be Su, since it's partially passive. Otherwise, I think it works fairly well.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.