Seasinger 
Creature — Merfolk
$0.24 #21172 0.11 31.8 years
When you control no Islands, sacrifice this creature.
You may choose not to untap this creature during your untap step.
: Gain control of target creature whose controller controls an Island for as long as you control this creature and this creature remains tapped.Click a line or tag to filter
Cards similar to Seasinger 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.
Sea Serpent92%
$0.09↓#28803↓0.24↑33.1 years↑
"When you control no Islands, sacrifice this creature."
+1 more matching line
Manta Ray92%
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"When you control no Islands, sacrifice this creature."
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Slipstream Serpent92%
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"When you control no Islands, sacrifice this creature."
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Dandân90%
$1.96↑#215070.1232.7 years
"When you control no Islands, sacrifice this creature."
+1 more matching line
Vodalian Knights88%
$1.01↑#29614↓0.24↑31.8 years
"When you control no Islands, sacrifice this creature."
+1 more matching line
Pirate Ship88%
$0.50↑#216680.48↑33.1 years↑
"When you control no Islands, sacrifice this creature."
+1 more matching line
Skeleton Ship88%
$6.19↑#206430.00↓31.3 years
"When you control no Islands, sacrifice this card."
Merchant Ship88%
$43.78↑#28544↓0.42↑32.7 years
"When you control no Islands, sacrifice this creature."
+1 more matching line
Island Fish Jasconius87%
$0.32↑#26571↓0.42↑32.7 years
"When you control no Islands, sacrifice this creature."
+2 more matching lines
Giant Shark86%
$0.29↑#25631↓0.30↑32.1 years
"When you control no Islands, sacrifice this creature."
+1 more matching line
Kukemssa Serpent86%
$0.11↓#28620↓0.47↑29.9 years↓
"When you control no Islands, sacrifice this creature."
+1 more matching line
Gorilla Pack85%
$0.17↓#26683↓0.25↑31.3 years
"When you control no Forests, sacrifice this creature."
Barbarian Outcast84%
$0.09↓#31013↓0.53↑24.6 years↓
"When you control no Swamps, sacrifice this creature."
Bog Serpent84%
$0.10↓#30513↓0.00↓19.6 years↓
"When you control no Swamps, sacrifice this creature."
Marjhan84%
$0.56↑#29322↓0.76↑30.9 years
"When you control no Islands, sacrifice this creature."
+2 more matching lines
Ronom Serpent80%
$0.09↓#27855↓0.53↑20.1 years↓
"When you control no snow lands, sacrifice this creature."
Serendib Djinn78%
$151.56↑#28023↓0.44↑32.7 years
"When you control no lands, sacrifice this creature."
Rubinia Soulsinger78%
$0.38↑#190600.48↑32.3 years
": Gain control of target creature for as long as you control this card and this card remains tapped."
: Gain control of target creature for as long as you control this card and this card remains tapped."+1 more matching line
Old Man of the Sea74%
$228.67↑#25932↓1.00↑32.7 years
"You may choose not to untap this creature during your untap step."
+1 more matching line
Emperor Crocodile74%
$0.13↓#28826↓0.53↑27.2 years↓
"When you control no other creatures, sacrifice this creature."