Guildscorn Ward
Gatecrash β common
Enchantment β Aura
Guildscorn Ward rulings:
2013-01-24: The enchanted creature canβt be enchanted or equipped by multicolored Auras and Equipment, it canβt be blocked by multicolored creatures, it canβt be targeted by multicolored spells or abilities from multicolored sources, and all damage dealt to it by multicolored sources is prevented.
2013-01-24: Hybrid spells and permanents in the Return to Ravnica block are multicolored, even if you cast them with one color of mana.