If you have two copies of "Fairy Box" active on the field you may flip a coin twice, but only need to call 1 correctly to reduce the attacking monster’s ATK to 0.
The current ATK is reduced to 0, including all Equip Spell Cards. Trap Cards and Quick-Play Spell Cards cannot further increase the monster’s ATK this battle. A monster effect such as "Injection Fairy Lily" can increase its own ATK after "Fairy Box" is successful.
Paying 500 Life Points is optional, if you choose not to pay "Fairy Box" is destroyed.
The effect of "Fairy Box" does not target, so "Lord of D." will not prevent "Fairy Box" from reducing the ATK of an attacking Dragon-Type monster to 0.