Gloom | Magic: The Gathering
Formats Gloom is Legal in
Official Oracle Text for Gloom
Activated abilities of white enchantments cost more to activate.
Official Rulings for Gloom
10/4/2004 : The additional mana is paid at the same time the spell/ability is cast/activated.
10/4/2004 : The extra mana is part of the total cost, so cost reducers can be applied to this cost.
7/1/2013 : Activated abilities contain a colon. They're generally written "[Cost]: [Effect]." Some keywords are activated abilities; they have colons in their reminder text.