Cheapest priced copy (Edge of Eternities): $47.99 at Card Kingdom, near mint, their price list as of .
Ouroboroid 
Creature — Plant Wurm · 1/3 · Mythic · Edge of Eternities · #345
At the beginning of combat on your turn, put X +1/+1 counters on each creature you control, where X is this creature's power.
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
4 printings · $47.99 to $84.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Edge of Eternities | 201 | Mythic | $47.99 | $54.99 |
| Edge of Eternities | 345 | Mythic | $57.99 | $84.99 |
| Edge of Eternities Promos | 201p | Mythic | $57.99 | $59.99 |
| Edge of Eternities Promos | 201s | Mythic | — | $64.99 |
2 rulings from Wizards of the Coast
- 25 July 2025The value of X is calculated only once, as Ouroboroid’s ability resolves.
- 25 July 2025If Ouroboroid leaves the battlefield before its ability resolves, use its power as it last existed on the battlefield to determine the value of X.