Liliana, Death Mage

[+1]: Return up to one target creature card from your graveyard to your hand.
[−3]: Destroy target creature. Its controller loses 2 life.
[−7]: Target opponent loses 2 life for each creature card in their graveyard.

The List

Core Set 2021

+1: Return up to one target creature card from your graveyard to your hand.
−3: Destroy target creature. Its controller loses 2 life.
−7: Target opponent loses 2 life for each creature card in their graveyard.

If the target creature is an illegal target by the time Liliana's second ability tries to resolve, the ability won't resolve. No player loses 2 life. If the target is legal but not destroyed (most likely because it has indestructible), its controller does lose 2 life.