Season of the Witch [The Dark] Green using their libraries as their

using their libraries as their decks

sacrifice Koskun Falls unless you tap an untapped creature you control

untap Mana Vault

Set: Amonkhet Invocations Type: Enchantment Rarity: Mythic Cost: {2}{U}{U} Tap an untapped creature you control: Tap target artifact

You may cast the copies without paying their mana costs

Season of the Witch [The Dark] Green using their libraries as theirSet: The Dark Type: Enchantment Rarity: Rare Cost: {B}{B}{B} At the beginning of your upkeep, sacrifice Season of the Witch unless you pay 2 life. At the beginning of the end step, destroy all untapped creatures that didn't attack this turn, except for creatures that couldn't attack.