Chandra's Incinerator

Text:

This spell costs less to cast, where X is the total amount of noncombat damage dealt to your opponents this turn.
Trample
Whenever a source you control deals noncombat damage to an opponent, Chandra's Incinerator deals that much damage to target creature or planeswalker that player controls.

Rulings:

• 6/23/2020 Combat damage is the damage that’s dealt automatically by attacking and blocking creatures. Any other damage is noncombat damage, even if it’s dealt during a combat phase by an attacking or blocking creature.
• 6/23/2020 Chandra’s Incinerator counts all noncombat damage dealt to your opponents, not the difference in their life totals since the turn began. For example, if an opponent was dealt 5 noncombat damage but gained 3 life, Chandra’s Incinerator still costs just <img src="/Handlers/Image.ashx?size=small&amp;name=R&amp;type=symbol" alt="Red" align="absbottom" />.
• 6/23/2020 The cost reduction applies only to generic mana in the cost of Chandra’s Incinerator. It can’t reduce the <img src="/Handlers/Image.ashx?size=small&amp;name=R&amp;type=symbol" alt="Red" align="absbottom" /> requirement.
• 6/23/2020 In a multiplayer game, Chandra’s Incinerator counts damage dealt to opponents who have lost the game.