Mirror Wall

Edison Card Text
Halve the ATK of all your opponent's attacking monsters. During each of your Standby Phases, pay 2000 Life Points or destroy this card.
Retro Pack 2 • 2009-07-24
No targeting
No Damage Step effect
Banlist • Unlimited
Interactions
What happens if I can't pay Mirror Wall's maintenance cost?✓
Your Life Points are 2000 or less when Mirror Wall's maintenance cost would be paid.
You cannot pay a cost that would reduce your Life Points to 0. If your LP are 2000 or less, you cannot pay Mirror Wall's optional maintenance cost, so Mirror Wall self-destructs.
How does Imperial Custom interact with Mirror Wall's maintenance?!
Mirror Wall is active while Imperial Custom is on the field.
Imperial Custom prevents the Trap from being destroyed by its own effect, so Mirror Wall can remain.
Rulings
edisonformat.net
●If Mirror Wall is already face-up on the field when a monster declares an attack, Mirror Wall reduces the ATK of the attacking monster by half when the attack is declared.
●If Mirror Wall is activated during an attack (including during the Damage Step), then it reduces the ATK of the attacking monster when Mirror Wall resolves. (Even though Mirror Wall normally reduces the attack by half when the attack is declared, it will still reduce the attack by half if you activate it after the attack is declared.)
●If Mirror Wall halves the ATK of a monster, it remains halved as long as Mirror Wall remains face-up on the field. If Mirror Wall is removed from the field, the ATK of the monsters is restored.
●If a monster attacks twice (over 2 turns, or if “Black Luster Soldier – Envoy of the Beginning” attacks twice in a row, etc.), its ATK is still only reduced by half once. So “Black Luster Soldier – Envoy of the Beginning” will have 1500 ATK for both of its attacks, for example.
●If you have 2 copies of Mirror Wall, and a monster attacks, its ATK is one-quarter. So “Blue-Eyes White Dragon” would have 750 ATK, for example. If 1 of the Mirror Wall copies leaves play, then the ATK is increased to half (if both copies leave play, the ATK is restored to full.)
●You can activate Mirror Wall during the Damage Step before damage calculation.
●The effect of Mirror Wall does not target.
●Reverse Trap will have no effect on Mirror Wall.
edisonformat.com
If "Mirror Wall" is already face-up on the field when a monster declares an attack, "Mirror Wall" reduces the ATK of the attacking monster by half when the attack is declared.
If "Mirror Wall" is activated during an attack (including during the Damage Step), then it reduces the ATK of the attacking monster when "Mirror Wall" resolves. (Even though "Mirror Wall" normally reduces the attack by half when the attack is declared, it will still reduce the attack by half if you activate it after the attack is declared.)
If "Mirror Wall" halves the ATK of a monster, it remains halved as long as "Mirror Wall" remains face-up on the field. If "Mirror Wall" is removed from the field, the ATK of the monsters is restored.
If a monster attacks twice (over 2 turns, or if “Black Luster Soldier – Envoy of the Beginning” attacks twice in a row, etc.), its ATK is still only reduced by half once. So “Black Luster Soldier – Envoy of the Beginning” will have 1500 ATK for both of its attacks, for example.
If you have 2 copies of "Mirror Wall", and a monster attacks, its ATK is one-quarter. So “Blue-Eyes White Dragon” would have 750 ATK, for example. If 1 of the "Mirror Wall" copies leaves play, then the ATK is increased to half (if both copies leave play, the ATK is restored to full.)
You can activate "Mirror Wall" during the Damage Step before damage calculation.
The effect of "Mirror Wall" does not target.
"Reverse Trap" will have no effect on "Mirror Wall".