Xantid Swarm {G}
Creature — Insect
Flying
Whenever this creature attacks, defending player can't cast spells this turn.
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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.
Wardscale Dragon 90%
$0.17#20053
"As long as this creature is attacking, defending player can't cast spells."
+1 more matching line
Ogre Marauder 89%
$0.25#24804
"Whenever this creature attacks, it gains "this creature can't be blocked" until end of turn unless defending player sacrifices a creature of their choice."
Yuan Shao's Infantry 89%
$5.31#31156
"Whenever this creature attacks alone, this creature can't be blocked this combat."
Hardened Berserker 89%
$0.03#23580
"Whenever this creature attacks, the next spell you cast this turn costs {1} less to cast."
Smirking Spelljacker 88%
$2.79#6873
"Whenever this creature attacks, if a card is exiled with it, you may cast the exiled card without paying its mana cost."
Abyssal Nightstalker 88%
$0.50#27330
"Whenever this creature attacks and isn't blocked, defending player discards a card."
Stromgald Spy 88%
$0.15#29721
"Whenever this creature attacks and isn't blocked, you may have defending player play with their hand revealed for as long as this creature remains on the battlefield. If you do, this creature assigns no combat damage this turn."
Flockchaser Phantom 87%
$0.28#13180
"Whenever this creature attacks, the next spell you cast this turn has convoke."
Shrieking Specter 87%
$1.08#30458
"Whenever this creature attacks, defending player discards a card."
+1 more matching line
Goblin Maskmaker 86%
$0.11#21018
"Whenever this creature attacks, face-down spells you cast this turn cost {1} less to cast."
Command of Unsummoning 86%
$0.16#28239
"Cast this spell only during the declare attackers step and only if you've been attacked this step."
Treetop Defense 86%
$0.56#31357
"Cast this spell only during the declare attackers step and only if you've been attacked this step."
Remove 86%
$0.47#30333
"Cast this spell only during the declare attackers step and only if you've been attacked this step."
Assassin's Blade 86%
$0.35#23383
"Cast this spell only during the declare attackers step and only if you've been attacked this step."
Rally the Troops 86%
$11.18#26559
"Cast this spell only during the declare attackers step and only if you've been attacked this step."
Warrior's Stand 86%
$10.88#30153
"Cast this spell only during the declare attackers step and only if you've been attacked this step."
Scorching Winds 86%
$0.24#28959
"Cast this spell only during the declare attackers step and only if you've been attacked this step."