Karn\'s Closet of Tomfoolery

Whenever Karn blocks or becomes blocked, it gets -4/+4 until end of turn. : Target noncreature artifact becomes an artifact creature with power and toughness each equal to its mana value until end of turn.

When this artifact enters, exile the top five cards of target player's library face down. You may look at those cards for as long as they remain exiled. , , Put a card exiled with this artifact into its owner's graveyard: Counter target spell if it has the same name as that card.

At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.