Emrakul, the Aeons Torn [Rise of the Eldrazi Prerelease Promos]

This spell can't be countered.
When you cast this spell, take an extra turn after this one.
Flying, protection from colored spells, annihilator 6
When Emrakul, the Aeons Torn is put into a graveyard from anywhere, its owner shuffles their graveyard into their library.