Jack's Knight [EEN-EN005] Ultimate Rare Gold Secret Rare You can only use this

You can only use this effect once per turn during your Main Phase

You can also Special Summon up to 2 "Nimble Momongas" from your Deck in face-down Defense Position

Set: Shonen Jump Magazine Promos Card type: Effect Monster Rarity: Ultra Rare Attack: 1400 Defense: 1400 If your opponent's monster attacks this face-down Defense Position card

all monsters your opponent currently controls lose 300 ATK for each

The Dimension Force booster set contains 100 new cards:

Jack's Knight [EEN-EN005] Ultimate Rare Gold Secret Rare You can only use thisSet: Elemental Energy Card type: Normal Monster Rarity: Ultimate Rare Attack: 1900 Defense: 1000