Hall of Gemstone [Mirage] Dragon you may change "swampwalk" to

you may change "swampwalk" to "plainswalk

Set: Limited Edition Alpha Type: Instant Rarity: Uncommon Cost: {B} As an additional cost to cast this spell

Set: Limited Edition Alpha Type: Instant Rarity: Common Cost: {X}{W} Prevent the next X damage that would be dealt to any target this turn

Set: Revised Edition Type: Instant Rarity: Uncommon Cost: {W} Exile target creature

Hall of Gemstone [Mirage] Dragon you may change "swampwalk" toSet: Mirage Type: World Enchantment Rare Cost: {1}{G}{G} At the beginning of each player's upkeep, that player chooses a color. Until end of turn, lands tapped for mana produce mana of the chosen color instead of any other color.