Adding a "loseAbilities" keyword per Dr.Solomat's request. The Goal was to code Evil Presence, but I think there is still some work to do to achieve this. The main concern is that (according to the Miki), neither transforms(( nor "becomes(" allow to lose some subtypes. A land enchanted with Evil Presence is supposed to lose its land subtypes. Since we don't support subtypes that good, I don't think this is possible. Additionally, Evil PResence would require to move "{T}:Add{X}" from the basic lands primitives into the rules (which sounds quite easy to do). I've nevertheless tested this on Gaea's Cradle, and it works. (Gaea's Cradle loses its abilities)

projects/mtg/bin/Res/sets/primitives/unsupported.txt

@@ -6574,8 +6574,13 @@ power=2
 toughness=2
 [/card]
 [card]
+#Need a way for the target to lose its land subtypes.
+#Need to move the {T}:Add{X} rules for basic lands outside of the cards and into the rules <-- easy?
 name=Evil Presence
 text=Enchant land -- Enchanted land is a Swamp.
+target=land
+auto=loseabilities
+auto=transforms((swamp,))
 mana={B}
 type=Enchantment
 subtype=Aura