Drought

{2}{W}{W} · Enchantment

At the beginning of your upkeep, sacrifice this enchantment unless you pay {W}{W}. Spells cost an additional "Sacrifice a Swamp" to cast for each black mana symbol in their mana costs. Activated abilities cost an additional "Sacrifice a Swamp" to activate for each black mana symbol in their activation costs.

Motor: se resuelve a mano

Rulings (3)

Activated abilities contain a colon. They’re generally written “[Cost]: [Effect].” Some keywords are activated abilities and will have colons in their reminder text.
Wizards of the Coast · 2016-06-08
A hybrid symbol that is both black and another type is a black mana symbol, regardless of what cost is paid for it.
Wizards of the Coast · 2008-08-01
You have to sacrifice a Swamp for each black mana in the activation cost. If you use Pestilence with {B}{B}{B}{B}, that’s 4 activations with {B} each so you sacrifice 4 Swamps.
Wizards of the Coast · 2004-10-04