"The time of condemnation is at hand. Dusk washes over the world, and I consign you to eternal darkness!"

Moment of Craving

Target creature gets -2/-2 until end of turn. You gain 2 life.

Foundations Jumpstart

The vampires of the Dusk Legion undertake Blood Fasts to strengthen their wills, but not all can control their hunger.

Foundations

Jumpstart 2022

The List

Rivals of Ixalan

If the target creature is an illegal target by the time Moment of Craving tries to resolve, it won't resolve and none of its effects will happen. You won't gain 2 life.

The target creature will still be on the battlefield when you gain life, even if its toughness has been reduced to 0 or less. Any abilities it has that interact with gaining life do so as appropriate. If any abilities trigger on you gaining life, the creature will be put into its owner's graveyard after that ability triggers but before it resolves.