Cheapest priced copy (Foundations Commander): $3.49 at Card Kingdom, near mint, their price list as of .
Arachnogenesis 
Instant · Rare · Commander Masters · #647
Create X 1/2 green Spider creature tokens with reach, where X is the number of creatures attacking you. Prevent all combat damage that would be dealt this turn by non-Spider creatures.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
7 printings · $3.49 to $16.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2015 | 32 | Rare | $8.49 | — |
| Commander Masters | 272 | Rare | $7.99 | $8.99 |
| Commander Masters | 553 | Rare | — | — |
| Commander Masters | 647 | Rare | $9.49 | $9.99 |
| Duskmourn: House of Horror Commander | 169 | Rare | $8.49 | — |
| Foundations Commander | 187 | Rare | $3.49 | — |
| Marvel Universe | 31 | Mythic | $9.99 | $16.99 |