Pain for All 

Enchantment — Aura
Enchant creature you control
When this Aura enters, enchanted creature deals damage equal to its power to any other target.
Whenever enchanted creature is dealt damage, it deals that much damage to each opponent.
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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.
Super State 88%
$22.00#2574
"Whenever enchanted creature deals combat damage to an opponent, it deals that much damage to each other opponent."
Curiosity 80%
$1.43#591
"Whenever enchanted creature deals damage to an opponent, you may draw a card."
+1 more matching line
Ophidian Eye 80%
$10.28#1682
"Whenever enchanted creature deals damage to an opponent, you may draw a card."