Infernal Darkness

{2}{B}{B} · Enchantment

Cumulative upkeep—Pay {B} and 1 life. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) If a land is tapped for mana, it produces {B} instead of any other type.

Motor: se resuelve a mano

Rulings (1)

This effect changes the type of mana produced, but not the amount. For example, if a land that's tapped for mana would add {W}{W}, it adds {B}{B} instead.
Wizards of the Coast · 2008-10-01