Exodia the Obliterator

Card text

When you draw this card during your turn: You can reveal it; Special Summon it. If this card is Special Summoned during your turn: You can activate this effect; for the rest of this turn, neither player can activate cards or effects, except "Exodia the Obliterator", also you cannot Normal or Special Summon monsters. At the start of the Damage Step, if this card battles: You can destroy as many monsters your opponent controls as possible, and if you do, inflict damage to your opponent equal to the total original ATK of those destroyed monsters.