Cannot be Normal Summoned Set. Must be Special Summoned by card effect. If a Drytron card is on the field: You can Special Summon this card from your hand or GY, but banish it when it leaves the field. If this card is Special Summoned: You can add 1 Drytron monster from your Deck to your hand, except Drytron Nu II . You can only use each effect of Drytron Nu II once per turn, also you cannot Ritual Summon the turn you activate either of this card s effects, except Machine monsters.