Fiery Confluence
Artist: Kieran Yanner TCG Player Link Scryfall Link EDHREC Link

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Fiery Confluence
Artist: Kieran Yanner TCG Player Link Scryfall Link EDHREC Link
So the Red Terror gets a +1/+1 counter every time a red source deals damage. Does it trigger multiple times if a red damage source hits multiple targets? Like dual shot, for example. Would that give me 1 or 2 +1/+1 counters
The Red Terror will trigger once for each time the verb "deals" is used in conjunction with damage being dealt. This means that a card like Dual Shot or Blasphemous Act only deals damage once, despite damaging multiple things. Similarly, combat damage is only a single trigger even if trample is involved. To get multiple triggers from the Red Terror, you'll need a multi-choice modal spell, such as Fiery Confluence, which has separate instances of damage being dealt. You'll get one trigger from each instance of each mode you chose that dealt damage.
Unfortunately, most spells and abilities are templated with only a single "deals" in the text and exceptions are few and far between.
Fiery Confluence by Micah Epstein
Fiery Confluence
Artist: Kieran Yanner TCG Player Link Scryfall Link EDHREC Link
Fiery Confluence
Artist: Kieran Yanner TCG Player Link Scryfall Link EDHREC Link
Fiery Confluence
Artist: Kieran Yanner TCG Player Link Scryfall Link EDHREC Link
Fiery Confluence
Artist: Kieran Yanner