Cheapest priced copy (Core Set 2019): $0.99 at Card Kingdom, near mint, their price list as of .
Chromium, the Mutable 
Legendary Creature — Elder Dragon · 7/7 · Mythic · Core Set 2019 · #214
Flash
This spell can't be countered.
Flying
Discard a card: Until end of turn, Chromium becomes a Human with base power and toughness 1/1, loses all abilities, and gains hexproof. It can't be blocked this turn.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $0.99 to $12.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Core Set 2019 | 214 | Mythic | $0.99 | $5.99 |
| Core Set 2019 Promos | 214s | Mythic | — | $12.99 |
5 rulings from Wizards of the Coast
- 13 July 2018Effects that raise or lower a creature's power and/or toughness, such as the effect of Titanic Growth, will apply to the creature no matter when they started to take effect. The same is true for any counters that change its power and/or toughness and effects that switch its power and toughness.
- 13 July 2018If Chromium gains an ability after its activated ability resolves, it will keep that ability.
- 13 July 2018Chromium stops being an Elder Dragon for the turn once its last ability has resolved. It's still a legendary creature named Chromium, the Mutable.
- 13 July 2018Activating Chromium's last ability after it has become blocked won't cause Chromium to become unblocked.
- 13 July 2018Chromium's activated ability overwrites all previous effects that set its base power and toughness to specific values. Any power- or toughness-setting effects that start to apply after that ability resolves will overwrite this effect.