Cheapest priced copy (Dominaria United): $0.49 at Card Kingdom, near mint, their price list as of .
Defiler of Instinct 
Creature — Phyrexian Kavu · 4/4 · Rare · Dominaria United · #119
First strike
As an additional cost to cast red permanent spells, you may pay 2 life. Those spells cost {R} less to cast if you paid life this way. This effect reduces only the amount of red mana you pay.
Whenever you cast a red permanent spell, this creature deals 1 damage to any target.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
4 printings · $0.49 to $2.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Dominaria United | 119 | Rare | $0.49 | $0.49 |
| Dominaria United | 406 | Rare | $0.79 | $0.79 |
| Dominaria United Promos | 119p | Rare | $0.79 | $2.99 |
| Dominaria United Promos | 119s | Rare | — | $1.99 |
2 rulings from Wizards of the Coast
- 9 September 2022You may only pay the additional cost once per permanent spell.
- 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!