Thunder Dragondark (SOFU-EN019) - Soul Fusion Unlimited

You can discard this card (Quick Effect); add 1 “Thunder Dragondark” from your Deck to your hand. If this card is banished, or sent from the field to the GY: You can add 1 “Thunder Dragon” card from your Deck to your hand, except “Thunder Dragondark”. You can only use 1 “Thunder Dragondark” effect per turn, and only once that turn.