Cheapest priced copy (Teenage Mutant Ninja Turtles Source Material): $14.99 at Card Kingdom, near mint, their price list as of .
All Will Be One 
Enchantment · Mythic · Teenage Mutant Ninja Turtles Source Material · #8
Whenever you put one or more counters on a permanent or player, this enchantment deals that much damage to target opponent, creature an opponent controls, or planeswalker an opponent controls.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
6 printings · $14.99 to $54.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Phyrexia: All Will Be One | 118 | Mythic | $18.99 | $17.99 |
| Phyrexia: All Will Be One | 352 | Mythic | — | $54.99 |
| Phyrexia: All Will Be One Promos | 118p | Mythic | $18.99 | $17.99 |
| Phyrexia: All Will Be One Promos | 118s | Mythic | — | $23.99 |
| Teenage Mutant Ninja Turtles Source Material | 8 | Mythic | $14.99 | $17.99 |
| Secret Lair Drop | 1888 | Mythic | — | $22.99 |
2 rulings from Wizards of the Coast
- 4 February 2023All Will Be One's ability will trigger any time you put one or more counters on a permanent or player. This might be due to a spell or ability resolving, a permanent you control entering the battlefield with counters, or combat damage from a source with toxic, infect, or wither.
- 4 February 2023If more than one creature with toxic deals combat damage to a player at the same time, those counters are placed as a single event, and the ability triggers one time.