Black Dementia

: Return three target cards from an opponent's graveyard to their hand. Return target creature card from your graveyard to the battlefield.

As this artifact enters, choose an opponent. At the beginning of the chosen player's upkeep, this artifact deals X damage to that player, where X is the number of cards in their hand minus 4.

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Flash (You may cast this spell any time you could cast an instant.) When this creature enters, untap another target creature you control.