If the targeted creature or player is an illegal target by the time the ability resolves, the entire ability will be countered. No cards will be put into your graveyard, and no damage will be dealt.

If you have two or fewer cards in your library when the ability resolves, all of them will be put into your graveyard. Heretic’s Punishment will still deal damage equal to the highest converted mana cost among those cards.

The converted mana cost of a double-faced card in your graveyard is the converted mana cost of the front face.

If all three cards have a converted mana cost of 0, no damage will be dealt.

If a split card is put into your graveyard this way, consider each cost individually. For example, if Crime/Punishment, a split card with converted mana costs of 2 and 5, is put into your graveyard as well as a land and a card with converted mana cost 6, 6 damage is dealt because 6 is greater than 5 and greater than 2.