Opal Gargoyle {1}{W}
Enchantment
When an opponent casts a creature spell, if this permanent is an enchantment, it becomes a 2/2 Gargoyle creature with flying.
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Cards that do something similar expected a card that isn't here?
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Opal Guardian 90%
$0.19#30162
"When an opponent casts a creature spell, if this permanent is an enchantment, this enchantment becomes a 3/4 Gargoyle creature with flying and protection from red."
Veil of Birds 85%
$0.14#28023
"When an opponent casts a spell, if this permanent is an enchantment, it becomes a 1/1 Bird creature with flying."
Opal Archangel 83%
$1.96#29198
"When an opponent casts a creature spell, if this permanent is an enchantment, it becomes a 5/5 Angel creature with flying and vigilance."