Cards like Opal Guardian

Opal Gargoyle91%

$0.16↓#303630.0727.9 years↑

"When an opponent casts a creature spell, if this permanent is an enchantment, it becomes a 2/2 Gargoyle creature with flying."

sleeping-enchantment, cast-trigger-other, gains-flying

Opal Titan90%

$0.47↑#298210.27↑27.9 years↑

"When an opponent casts a creature spell, if this permanent is an enchantment, it becomes a 4/4 Giant creature with protection from each of that spell's colors."

sleeping-enchantment, gains-protection, cast-trigger-other

Opal Archangel90%

$2.10↑#294730.53↑27.9 years↑

"When an opponent casts a creature spell, if this permanent is an enchantment, it becomes a 5/5 Angel creature with flying and vigilance."

sleeping-enchantment, cast-trigger-other, gains-flying

Veil of Birds90%

$0.15↓#283360.33↑27.9 years↑

"When an opponent casts a spell, if this permanent is an enchantment, it becomes a 1/1 Bird creature with flying."

sleeping-enchantment, cast-trigger-other, gains-flying

Opal Acrolith86%

$0.26↑#304330.29↑27.9 years↑

"Whenever an opponent casts a creature spell, if this permanent is an enchantment, it becomes a 2/4 Soldier creature."

sleeping-enchantment, cast-trigger-other, untracked-indefinite-effect

Opal Caryatid86%

$0.11↓#305350.0027.9 years↑

"When an opponent casts a creature spell, if this permanent is an enchantment, it becomes a 2/2 Soldier creature."

sleeping-enchantment, cast-trigger-other, untracked-indefinite-effect

Veiled Apparition84%

$0.18#315440.29↑27.9 years↑

"When an opponent casts a spell, if this permanent is an enchantment, it becomes a 3/3 Illusion creature with flying and "At the beginning of your upkeep, sacrifice this creature unless you pay

.""

sleeping-enchantment, cast-trigger-other, gains-flying

Hidden Spider81%

$0.29↑#20701↑0.14↑27.9 years↑

"When an opponent casts a creature spell with flying, if this permanent is an enchantment, it becomes a 3/5 Spider creature with reach."

sleeping-enchantment, cast-trigger-other, untracked-indefinite-effect

Opal Champion80%

$0.14↓#305820.44↑27.6 years↑

"When an opponent casts a creature spell, if this permanent is an enchantment, it becomes a 3/3 Knight creature with first strike."

sleeping-enchantment, cast-trigger-other, animate-self

Hidden Ancients80%

$0.23↑#275190.12↑27.9 years↑

"When an opponent casts an enchantment spell, if this permanent is an enchantment, it becomes a 5/5 Treefolk creature."

sleeping-enchantment, cast-trigger-other, untracked-indefinite-effect

Hidden Gibbons76%

$11.67↑#18930↑0.38↑27.6 years↑

"When an opponent casts an instant spell, if this permanent is an enchantment, it becomes a 4/4 Ape creature."

sleeping-enchantment, cast-trigger-other, animate-self

Lurking Skirge72%

$0.55↑#312560.0727.6 years↑

"When a creature is put into an opponent's graveyard from the battlefield, if this permanent is an enchantment, it becomes a 3/2 Phyrexian Imp creature with flying."

sleeping-enchantment, gains-flying, animate-self

Hidden Guerrillas72%

$0.37↑#259850.0727.9 years↑

"When an opponent casts an artifact spell, if this permanent is an enchantment, it becomes a 5/3 Soldier creature with trample."

sleeping-enchantment, cast-trigger-other, untracked-indefinite-effect

Veiled Sentry72%

$0.25↑#283650.19↑27.9 years↑

"When an opponent casts a spell, if this permanent is an enchantment, it becomes an Illusion creature with power and toughness each equal to that spell's mana value."

sleeping-enchantment, cast-trigger-other, animate-self