[Endoperez]

I have had this strange idea for some time... Although the sphinx cannot move, the spirit inhabiting the sphinx COULD if there there was somthing to move in.
As sphinx is just a pile of rocks just as castles why couldn't we build a new sphinx and let the pretender change 'bodies'. Of course, this also means that the physical Sphinx could be destroyed. It should be expensive (even 1000+ gp?), and it also would make it harder to call it back if he died. Also, shouldn't the sphinx be unable to heal? That should help out a lot. Few armor negating bows, high precision and some fodder, and time, and that would do it.
Also, isn't there an Earth spell giving out awesome amounts of damage to constructs? Does it need a MR check?

Same things for oracle, especially Blood Fountain would benefit from this.