Sequía

Text:

At the beginning of your upkeep, sacrifice Drought unless you pay .
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.

Rulings:

• 10/4/2004 You have to sacrifice a Swamp for each black mana in the activation cost. If you use Pestilence with <img src="/Handlers/Image.ashx?size=small&amp;name=B&amp;type=symbol" alt="Black" align="absbottom" /><img src="/Handlers/Image.ashx?size=small&amp;name=B&amp;type=symbol" alt="Black" align="absbottom" /><img src="/Handlers/Image.ashx?size=small&amp;name=B&amp;type=symbol" alt="Black" align="absbottom" /><img src="/Handlers/Image.ashx?size=small&amp;name=B&amp;type=symbol" alt="Black" align="absbottom" />, that’s 4 activations with <img src="/Handlers/Image.ashx?size=small&amp;name=B&amp;type=symbol" alt="Black" align="absbottom" /> each so you sacrifice 4 Swamps.
• 8/1/2008 A hybrid symbol that is both black and another type is a black mana symbol, regardless of what cost is paid for it.
• 6/8/2016 Activated abilities contain a colon. They’re generally written “[Cost]: [Effect].” Some keywords are activated abilities and will have colons in their reminder text.