Exxod, Master of the Guard (SD7-EN001) [Structure Deck: Invincible Fortress]

This card cannot be Normal Summoned or Set. This card cannot be Special Summoned except by Tributing 1 monster on your side of the field that includes "sphinx" in its card name. While this card is face-up on the field, each time an EARTH monster is Flip Summoned, inflict 1000 points of damage to your opponent's Life Points.