Heartfire

Instant

As an additional cost to cast this spell, sacrifice a creature or planeswalker.
Heartfire deals 4 damage to any target.

2019-05-03:
You must sacrifice exactly one creature or planeswalker to cast this spell; you can’t cast it without sacrificing one, and you can’t sacrifice additional permanents.
2019-05-03:
Players can respond to Heartfire only after it’s been cast and all its costs have been paid. No one can try to destroy the permanent you sacrificed to stop you from casting this spell.