Quote Originally Posted by Abd al-Azrad

Some points I'd like to see cleared up. First, the discrepancy in the creatures' speeds: the Momeh flies at 50', but the mob can only surge around at 20'. Can the Momeh fly away from the mob, or is it linked to them (as the description suggests)?
The mob is linked to the Momeh, but not the Momeh to the mob. It basically just uses them as a shield, though it can go where it wish.

Second, the mind-consumption works when the Momeh successfully grapples an opponent. Obviously, the key is not to get into grapple range, but if you do, it makes a touch attack, starts a grapple, and instantly has you making Will saves. I feel, at least, the creature should have to take an action to establish a Pin, before it can consume your mind- especially since it instantly, almost irreversably destroyes the PC.
Maybe, but then again there are dozens of monsters who have instant kill abilities at much lower levels than this and they don't even have to be grappled. Just an attack or a look is enough.

Third is the obvious problem that incorporeal creatures don't have physical bodies with which to grapple. It looks like you're just ignoring that here purposefully, which is fine, but should be stated explicitly- or, as in the case of the Spectral Lurker, give the Momeh an ability to use its hands as Ghost Touch weapons as it wishes.
Well, its not so much grabbing the body as its essence and mind that is intertwined with the body. Thats why it uses its dexterity modifiers. This isn't without precedent as Spirit Animals from Frostburn for example are incorporeal creatures with grappling abilities.

Fourth, can True Seeing or other magics get around its Born of Dream ability?
Its basically a displacement effect, so most likely it would.