Altar of Dementia
Artifact
Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.
"It is not that you will go mad. It is that you will beg for madness." —Volrath
Brom
Modern Horizons (MH1)
• #218Rulings
The number of cards the target player puts into their graveyard is equal to the power of the sacrificed creature as it last existed on the battlefield.
(wotc • 2019-06-14)
If the target player's library contains fewer cards than the sacrificed creature's power, all of those cards are put into that player's graveyard. That player won't lose the game until they try to draw from the empty library.
(wotc • 2019-06-14)
Rulings
The number of cards the target player puts into their graveyard is equal to the power of the sacrificed creature as it last existed on the battlefield.
(wotc • 2019-06-14)
If the target player's library contains fewer cards than the sacrificed creature's power, all of those cards are put into that player's graveyard. That player won't lose the game until they try to draw from the empty library.
(wotc • 2019-06-14)