7 Aug 2020
Cragganwick Cremator deals damage equal to the discarded creature card's power as it exists in your graveyard.
7 Aug 2020
You choose the target player or planeswalker when the ability is put onto the stack. You won't know how much damage will be dealt until the ability resolves.
7 Aug 2020
If you have no cards in hand when Cragganwick Cremator's ability resolves, you don't discard anything.
7 Aug 2020
If the target player or planeswalker is an illegal target by the time the ability tries to resolve, the ability won't resolve. You won't discard a card.