Karn, the Great Creator [War of the Spark Prerelease Promos] Classic Sixth Edition indestructible Kefnet the Mindful can't

indestructible Kefnet the Mindful can't attack or block unless you have seven or more cards in hand

Set: Legends Type: Legendary Creature — Elder Dragon Rare Cost: {2}{G}{G}{W}{W}{U}{U} Flying At the beginning of your upkeep

but soon formed again

Discard your hand

Karn, the Great Creator [War of the Spark Prerelease Promos] Classic Sixth Edition indestructible Kefnet the Mindful can'tSet: War of the Spark Prerelease Promos Type: Legendary Planeswalker Karn Rarity: Rare Cost: {4} Activated abilities of artifacts your opponents control can't be activated. +1: Until your next turn, up to one target noncreature artifact becomes an artifact creature with power and toughness each equal to its converted mana cost. 2: You may choose an artifact card you own from outside the game or in exile, reveal that card, and put it into your hand.