Pendulum Effect: You cannot Pendulum Summon monsters, except "D/D" monsters. This effect cannot be negated. Once, while this card is in your Pendulum Zone, you can negate an activated Spell effect that would inflict damage to you, then destroy this card.
Monster Effect: If this card is Normal or Special Summoned: You can send 1 "D/D" or "Dark Contract" card from your Deck to the Graveyard, except "D/D Savant Copernicus". You can only use this effect of "D/D Savant Copernicus" once per turn.