Cheapest priced copy (Dominaria United): $5.99 at Card Kingdom, near mint, their price list as of .
Defiler of Vigor 
Creature — Phyrexian Wurm · 6/6 · Rare · Dominaria United · #160
Trample
As an additional cost to cast green permanent spells, you may pay 2 life. Those spells cost {G} less to cast if you paid life this way. This effect reduces only the amount of green mana you pay.
Whenever you cast a green permanent spell, put a +1/+1 counter on each creature you control.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
4 printings · $5.99 to $9.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Dominaria United | 160 | Rare | $5.99 | $5.99 |
| Dominaria United | 412 | Rare | $7.99 | $7.99 |
| Dominaria United Promos | 160p | Rare | $7.99 | $7.99 |
| Dominaria United Promos | 160s | Rare | — | $9.49 |
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.