Cheapest priced copy (Dominaria United): $0.69 at Card Kingdom, near mint, their price list as of .
Defiler of Flesh 
Creature — Phyrexian Horror · 4/4 · Rare · Dominaria United · #400
Menace
As an additional cost to cast black permanent spells, you may pay 2 life. Those spells cost {B} less to cast if you paid life this way. This effect reduces only the amount of black mana you pay.
Whenever you cast a black permanent spell, target creature you control gets +1/+1 and gains menace until end of turn.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
4 printings · $0.69 to $1.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Dominaria United | 90 | Rare | $0.69 | $0.79 |
| Dominaria United | 400 | Rare | $1.49 | $0.79 |
| Dominaria United Promos | 90p | Rare | $1.49 | $1.99 |
| Dominaria United Promos | 90s | Rare | — | $0.99 |
2 rulings from Wizards of the Coast
- 9 September 2022Some players may make the mental shortcut that the Defilers effectively turn one of the colored mana symbols in the spell’s cost into a Phyrexian colored mana symbol. Despite the similarity in function, this ability does not cause the spells to have Phyrexian mana symbols in their costs. Sorry, Rage Extractor!
- 9 September 2022You may only pay the additional cost once per permanent spell.