I've run around 8 encounters with a shaman and his spirit, and many questions about it's properties have been raised.
Is the spirit unsubstantial? Does the spirit float? The spirit is supposedly anything the character wants it to be so if they pick an eagle can it fly and attack things hanging onto the ceiling etc.
Does anyone know of any relevant rules? Have any of you encountered these issues? What were your rulings?
The spirit is not insubstantial (in the strict sense). I.e., damage done to it isn't halved. Also, enemies can't move through its square, so it's substantial. It does, however, float: since it's a conjuration, and conjurations can float, the spirit companion can as well. Even if it's not a critter with wings.
In general, the spirit is treated as another ally, such that enemies cannot move through its square while allies can (but cannot stop in the square).
The spirit lasts until you dismiss it with a minor action, fall unconscious, you use Call Spirit Companion to conjure another spirit companion, or it takes enough damage (see below).
You can attack it with melee or ranged attacks. Any attack that does less than 10 + half your level in damage is ignored. Any attack that does damage equal to or greater than that figure causes the spirit to disappear and the shaman takes 5 + half your level in damage. Note this means that the spirit is unaffected by area or close attacks. I also take the wording of the power to mean that it's immune to auras.
My understanding is that the spirits are representations of the person. Thus it should not change regularly. In addition, the spirits are "generally 4-legged creatures" if I remember correctly from the book.
