Forbidden Droplet — Ruling

Regola generale

Regarding the『in response to this card's activation, your opponent cannot activate cards, or the effects of cards, with the same original type (Monster/Spell/Trap) as the cards sent to the Graveyard to activate this card』text:
This is not treated as an effect.

About this card's ① st effect:
It can be activated during the Damage Step, but only before reaching During Damage Calculation.
To activate this effect, send any number of cards from your hand and/or field to the Graveyard as a cost. (You cannot send more cards than the number of monsters currently on your opponent's field that this effect can be applied to.)
You can also choose an Effect Monster whose effects are already negated, even if its ATK is already zero. (Its ATK will still be halved, but will remain zero as a result.)