ETCHEDCheapest priced copy (Modern Horizons 3 Commander): $8.49 at Card Kingdom, near mint, their price list as of .
Morophon, the Boundless 
Legendary Creature — Shapeshifter · 6/6 · Mythic · Commander Masters · #453
Changeling (This card is every creature type.)
As Morophon enters, choose a creature type.
Spells of the chosen type you cast cost {W}{U}{B}{R}{G} less to cast. This effect reduces only the amount of colored mana you pay.
Other creatures you control of the chosen type get +1/+1.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
11 printings · $8.49 to $44.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander Masters | 3 | Mythic | $8.99 | $10.99 |
| Commander Masters | 453 | Mythic | — | — |
| Commander Masters | 669 | Mythic | $12.99 | $12.99 |
| Commander Masters | 1058 | Mythic | — | $27.99 |
| Modern Horizons 3 Commander | 157 | Mythic | $8.49 | $12.99 |
| Modern Horizons | 1 | Mythic | $8.49 | $13.99 |
| Judge Gift Cards 2021 | 1 | Mythic | — | $27.99 |
| The List | MH1-1 | Mythic | $9.49 | — |
| Modern Horizons Promos | 1p | Mythic | $10.99 | $17.99 |
| Secret Lair Drop | 1896 | Mythic | — | $44.99 |
| Secret Lair Drop | 1944 | Mythic | — | $20.99 |
5 rulings from Wizards of the Coast
- 14 June 2019If a spell has hybrid mana symbols in its mana cost, you choose which half you will be paying before determining the total cost. For example, if a spell of the chosen type costs {2}{W/U}{W/U}, you may choose for the cost to be {2}{W}{U} and then reduce it to {2}.
- 14 June 2019Morophon's effect reduces the total cost by up to one mana of each color. For example, if a spell of the chosen type costs {4}{R}{W}{W}, it will cost {4}{W} after applying Morophon's effect.
- 14 June 2019You must choose an existing creature type, such as Sliver or Warrior. Card types such as artifact, and supertypes such as legendary or snow, can't be chosen.
- 14 June 2019Cost reduction effects are applied after other cost modifiers, so Morophon can reduce additional costs or alternative costs of spells of the chosen type.
- 14 June 2019Because damage remains marked on a creature until the damage is removed as the turn ends, nonlethal damage dealt to other creatures you control of the chosen type may become lethal if Morophon leaves the battlefield during that turn.