Heroism 

Enchantment
Sacrifice a white creature: For each attacking red creature, prevent all combat damage that would be dealt by that creature this turn unless its controller pays {2}{R}.
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Cards that do something similar expected a card that isn't here?
Reports become test cases the matcher is graded against before an update ships. Delvefall isn't a chatbot guessing, it compares the printed rules text of every card with plain math, and examples like yours decide which differences should count.