[quote]The Graveminds are Precursor remains, and thus they have Will's. Oryx converts the Wills of lesser beings to Take them, and therefore, in paper, he could take a Gravemind. That being said, more advanced Graveminds are likely too powerful to convert.[/quote] I can say with compleat certainty that he can't take a Gravemind, as their will is that of the Primordial, 1000 other Precursors, and all who have been consumed by the flood. But without a Gravemind it's possible.