Magnetic Mountain 
Enchantment
$0.41 #23407 1.08 32.8 years
Blue creatures don't untap during their controllers' untap steps.
At the beginning of each player's upkeep, that player may choose any number of tapped blue creatures they control and pay 
for each creature chosen this way. If the player does, untap those creatures.
for each creature chosen this way. If the player does, untap those creatures.Click a line or tag to filter
Cards similar to Magnetic Mountain 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.
Thelon's Curse100%
$0.63↑#31915↓0.84↓32.0 years
"Blue creatures don't untap during their controllers' untap steps."
+1 more matching line
Mudslide91%
$6.71↑#198130.90↓31.4 years↓
"At the beginning of each player's upkeep, that player may choose any number of tapped creatures without flying they control and pay 
for each creature chosen this way. If the player does, untap those creatures."
for each creature chosen this way. If the player does, untap those creatures."+1 more matching line
Dream Tides89%
$0.41#18339↑1.54↑29.7 years↓
"At the beginning of each player's upkeep, that player may choose any number of tapped nongreen creatures they control and pay for each creature chosen this way. If the player does, untap those creatures."
for each creature chosen this way. If the player does, untap those creatures."+1 more matching line
Wrath of Marit Lage82%
$0.33↓#245391.35↑31.4 years↓
"Red creatures don't untap during their controllers' untap steps."
Intruder Alarm79%
$3.71↑#1735↑1.51↑28.6 years↓
"Creatures don't untap during their controllers' untap steps."
Riptide77%
$0.30↓#29225↓0.73↓32.2 years
"Tap all blue creatures."
An-Zerrin Ruins73%
$3.14↑#219911.1531.1 years↓
"Creatures of the chosen type don't untap during their controllers' untap steps."
Blizzard72%
$0.83↑#28621↓0.61↓31.4 years↓
"Creatures with flying don't untap during their controllers' untap steps."
Juntu Stakes71%
$0.29↓#257200.73↓26.0 years↓
"Creatures with power 1 or less don't untap during their controllers' untap steps."
Smoke70%
$7.41↑#6581↑1.72↑33.2 years
"Players can't untap more than one creature during their untap steps."
Crackdown70%
$1.00↑#12491↑1.27↑27.0 years↓
"Nonwhite creatures with power 3 or greater don't untap during their controllers' untap steps."
Blue Scarab70%
$0.24↓#252420.25↓31.4 years↓
"Enchanted creature gets +2/+2 as long as an opponent controls a blue permanent."
Magistrate's Veto70%
$0.25↓#254960.42↓27.0 years↓
"White creatures and blue creatures can't block."
Mudbrawler Raiders70%
$0.21↓#31475↓0.11↓18.5 years↓
"This creature can't be blocked by blue creatures."
Energy Storm70%
$1.41↑#276991.1231.4 years↓
"Creatures with flying don't untap during their controllers' untap steps."