Copycrook {2}{U}{U}
Creature — Shapeshifter Rogue
You may have this creature enter as a copy of any creature on the battlefield, except it has "Whenever this creature attacks, it connives." (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)
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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.
Jwari Shapeshifter 89%
$3.79#10849
"You may have this creature enter as a copy of any Ally creature on the battlefield."
Auton Soldier 88%
$10.83#2016
"You may have this creature enter as a copy of any creature on the battlefield, except it isn't legendary, is an artifact in addition to its other types, and has myriad."
Stunt Double 87%
$4.51#3870
"You may have this creature enter as a copy of any creature on the battlefield."
Naga Fleshcrafter 87%
$0.33#5377
"You may have this creature enter as a copy of any creature on the battlefield."
Clone 87%
$0.63#3831
"You may have this creature enter as a copy of any creature on the battlefield."
Progenitor Mimic 86%
$1.38#5243
"You may have this creature enter as a copy of any creature on the battlefield, except it has "At the beginning of your upkeep, if this creature isn't a token, create a token that's a copy of this creature.""
Redoubled Stormsinger 86%
$0.25#3402
"Whenever this creature attacks, for each creature token you control that entered this turn, create a tapped and attacking token that's a copy of that token. At the beginning of the next end step, sacrifice those tokens."
Undercover Operative 85%
$0.37#5367
"You may have this creature enter as a copy of any creature on the battlefield, except it enters with a shield counter on it if you control that creature."
Protean Raider 85%
$0.58#13014
"If you attacked this turn, you may have this creature enter as a copy of any creature on the battlefield."
Gigantoplasm 85%
$0.59#9543
"You may have this creature enter as a copy of any creature on the battlefield, except it has "{X}: This creature has base power and toughness X/X.""
Vizier of Many Faces 84%
$0.30#4322
"You may have this creature enter as a copy of any creature on the battlefield, except if this creature was embalmed, the token has no mana cost, it's white, and it's a Zombie in addition to its other types."
Phyrexian Metamorph 84%
$2.32#306
"You may have this creature enter as a copy of any artifact or creature on the battlefield, except it's an artifact in addition to its other types."
Pirated Copy 84%
$7.51#8155
"You may have this creature enter as a copy of any creature on the battlefield, except it's a Pirate in addition to its other types and it has "Whenever this creature or another creature with the same name deals combat damage to a player, you draw a card.""
Vesuvan Doppelganger 84%
#16958
"You may have this creature enter as a copy of any creature on the battlefield, except it doesn't copy that creature's color and it has "At the beginning of your upkeep, you may have this creature become a copy of target creature, except it doesn't copy that creature's color and it has this ability.""
Cyclops Gladiator 84%
$0.17#23913
"Whenever this creature attacks, you may have it deal damage equal to its power to target creature defending player controls. If you do, that creature deals damage equal to its power to this creature."
Hulking Metamorph 84%
$0.18#7907
"You may have this creature enter as a copy of an artifact or creature you control, except it's an artifact creature in addition to its other types, and its power and toughness are equal to this creature's power and toughness."
Synth Infiltrator 83%
$0.25#8793
"You may have this creature enter as a copy of any creature on the battlefield, except it's a Synth artifact creature in addition to its other types."