Agonizing Remorse

If you choose a card from their graveyard, it may be a land card.

You must choose a card to exile if able. If there are no nonland cards in the opponent's hand, you must exile a card from their graveyard, and vice versa.

No player may take actions between the time you choose a card and the time it's exiled.

If there are no nonland cards in their hand and no cards in their graveyard, then you just lose 1 life.