Cheapest priced copy (The Brothers' War Retro Artifacts): $19.99 at Card Kingdom, near mint, their price list as of .
Altar of Dementia 
Artifact · Rare · Modern Horizons · #218
Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
6 printings · $19.99 to $44.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| The Brothers' War Retro Artifacts | 3 | Mythic | $19.99 | $34.99 |
| The Brothers' War Retro Artifacts | 66 | Mythic | $32.99 | $39.99Out of stock |
| The Brothers' War Retro Artifacts | 66z | Mythic | — | — |
| Conspiracy | 196 | Rare | $22.99 | $44.99 |
| Modern Horizons | 218 | Rare | $20.99 | $34.99 |
| Tempest | 276 | Rare | $29.99 | — |
2 rulings from Wizards of the Coast
- 14 June 2019The number of cards the target player puts into their graveyard is equal to the power of the sacrificed creature as it last existed on the battlefield.
- 14 June 2019If the target player's library contains fewer cards than the sacrificed creature's power, all of those cards are put into that player's graveyard. That player won't lose the game until they try to draw from the empty library.