Would an magical hologram count as incorporeal?

[MonkeySage]

In one of my games, my player witnessed an orc get possessed by an unidentified shadowy object. When the orc was destroyed, the object emerged and took on the appearance of a long dead friend of the player.

Object was completely unaffected by efforts to restrain it, enchanted crossbow bolts passed right through it, and true seeing showed the object in the above mentioned appearance.

It doesn't register as magical, and even though it seems incapable of touching the bolts or being affected by them, it looks solid.

My idea is that this object(it isn't an entity) is a primordial force older than the gods and predating the existence of magic in its current form.

For what reason might true seeing not show its true form? If it has no true form, would it appear as invisible?

The object is meant to be beyond mortal or divine comprehension.

The object is a manifestation of Evil as a cosmic force; Evil in its most primal state.

[Socksy]

They're seeing a lump of Evil?
No, it wouldn't count as incorporeal, that would give magic weapons a chance to affect it (unless Beastie also has DR or immunity to weapons).

[sovin_ndore]

I would probably stat this "manifestation" as a Project Image spell... maybe as if cast by a shadowcraft mage. It only takes a cantrip to affect auras so it could be that simple. As to the power behind this, the sky is the limit... it could be Cthulu if you wanted.

[Thrudd]

If the object is beyond divine comprehension, meaning it was not created by the gods of your world and is outside their purview/dominion, then it might make sense that it is unaffected by any sort of magic the players have access to. True Seeing, and pretty much any other spell, simply doesn't work on it, regardless of it's true appearance.
immune to spells/magic, immune to physical attacks, immune to divine intervention, immune to comprehension. You can only affect it if you travel to its native universe/dimension somehow, which is outside the "great wheel" cosmos. Maybe they need to hop on a spelljammer and fly to a different crystal sphere where this thing is being projected from.

[Mastikator]

It might be epic, or it might even genuinely not be magical.

A hologram wouldn't count as incorporeal, nor as an illusion since it's actually there. It would count as a light-show, probably evocation based if it's magical.

Yeah that's probably it. An epic evocation spell-blob that creates a non-magical lightshow hologram and physically forces movement of creatures it possesses.

[MonkeySage]

Well, the thing as the ability to possess, but can only possess willing subjects; the result is that the creature possessed is basically under a form of mind control that comes with a power boost. A proxy(possessed creature) is an enhanced version of their usual type.

This evil force is incapable of directly influencing the world through physical contact, but can spread Taint by way of its proxies. Mostly it toys with the minds of those who've committed evil acts in the past, using those evil acts to manipulate the victim.