Cheapest priced copy (Ice Age): $3.99 at Card Kingdom, near mint, their price list as of .
Infernal Darkness 
Enchantment · Rare · Ice Age · #135
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.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
1 printing · $3.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Ice Age | 135 | Rare | $3.99 | — |
One ruling from Wizards of the Coast
- 1 October 2008This 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.