FOILCheapest priced copy (Aether Revolt): $0.99 at Card Kingdom, near mint, their price list as of .
Tezzeret the Schemer 
Legendary Planeswalker — Tezzeret · Mythic · Aether Revolt Promos · #137s
+1: Create a colorless artifact token named Etherium Cell with "{T}, Sacrifice this token: Add one mana of any color."
−2: Target creature gets +X/-X until end of turn, where X is the number of artifacts you control.
−7: You get an emblem with "At the beginning of combat on your turn, target artifact you control becomes an artifact creature with base power and toughness 5/5."
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $0.99 to $6.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Aether Revolt | 137 | Mythic | $0.99 | $2.49 |
| Aether Revolt Promos | 137s | Mythic | — | $6.49 |
6 rulings from Wizards of the Coast
- 9 February 2017An artifact that becomes a creature due to the emblem's ability can't attack unless you've controlled it continuously since your turn began. It doesn't matter whether or not it was a creature at that time.
- 9 February 2017The effect of the emblem's triggered ability lasts indefinitely.
- 9 February 2017The value of X for Tezzeret's second ability is determined only as the ability resolves. It won't change later in the turn if the number of artifacts you control changes.
- 9 February 2017If an Equipment becomes a creature, it becomes unattached and it can't be attached to a creature.
- 9 February 2017An artifact creature targeted by the emblem's ability becomes 5/5 instead of its normal power and toughness.
- 9 February 2017A Vehicle targeted by the emblem's ability becomes a 5/5 creature. Crewing it won't change its power and toughness.