No third-party market for this printing. Some promo runs (Salvat, McDonald's, Trainer Kits) do clear at private sales — record your own observation to anchor a price for this card.
If a source would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.
Legalities
tlrnot legal
duellegal
brawlnot legal
pennylegal
PreDH
Rulings · 5
wotc
If multiple effects modify how damage will be dealt, the player who would be dealt damage or the controller of the creature that would be dealt damage chooses the order to apply the effects. For example, Mending Hands says, “Prevent the next 4 damage that would be dealt to any target this turn.” Suppose a spell would deal 5 damage to a player who has cast Mending Hands targeting themselves. That player can either (a) prevent 4 damage first and then let Furnace of Rath double the remaining 1 damage, taking 2 damage, or (b) double the damage to 10 and then prevent 4 damage, taking 6 damage.
wotc
If you have two of these on the battlefield, the damage is multiplied by 4.
wotc
The multiplied damage counts in all ways as if it came from the original source. Furnace of Rath is not the source.
Notes
No price observations yet — this card is in the canonical catalog but a refresh hasn't seen a market price.
If a spell or ability damages multiple things, divide up the damage before applying this effect. This means you can’t normally end up with an odd amount of damage on something.
wotc
The trample rules cause damage to be divided before it is doubled.
