Magic Jammer [RP01-EN046] Common Green;Black that monster's effect(s) is nagated

that monster's effect(s) is nagated during that Battle Phase

the ATK and DEF of all face-up monsters your opponent controls become half their current ATK and DEF (even if this card leaves the field)

You cannot Normal Summon or Set the turn you activate this effect

Set: Base Set Unlimited Type: Colorless Rarity: Rare Retreat cost: Colorless

Set: Power of the Duelist Card type: Effect Monster Rarity: Super Rare Attack: 3400 Defense: 2400 This card cannot be Normal Summoned or Set

Magic Jammer [RP01-EN046] Common Green;Black that monster's effect(s) is nagatedSet: Retro Pack 1 Card type: Counter Trap Rarity: Common Discard 1 card. Negate the activation of a Spell Card and destroy it.