Cheapest priced copy (Marvel's Spider-Man): $99.99 at Card Kingdom, near mint, out of stock, their price list as of .
The Soul Stone 
Legendary Artifact — Infinity Stone · Mythic · Marvel's Spider-Man · #66
Indestructible
{T}: Add {B}.
{6}{B}, {T}, Exile a creature you control: Harness The Soul Stone. (Once harnessed, its ∞ ability is active.)
∞ — At the beginning of your upkeep, return target creature card from your graveyard to the battlefield.
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
4 printings · $99.99 to $44999.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Marvel's Spider-Man Promos | 66s | Mythic | — | $229.99 |
| Marvel's Spider-Man | 66 | Mythic | $99.99Out of stock | $179.99 |
| Marvel's Spider-Man | 242 | Mythic | — | $44999.99Out of stock |
| Marvel's Spider-Man | 243 | Mythic | — | $2499.99 |
3 rulings from Wizards of the Coast
- 19 September 2025Being harnessed isn't copiable. If something else becomes a copy of The Soul Stone, it must be harnessed separately. Similarly, if The Soul Stone is already harnessed and becomes a copy of something else, it stays harnessed, though it's very likely that won't be relevant until that copy effect ends.
- 19 September 2025Until it is harnessed, The Soul Stone doesn't have the ability listed after the infinity symbol. It also doesn't have that ability in zones other than the battlefield.
- 19 September 2025"Harnessed" is a designation that the permanent has once an ability instructs you to harness it. It has no special rules meaning other than being a designation that the ∞ ability (and, theoretically, other effects) can see.