Cheapest priced copy (Aetherdrift Commander): $1.29 at Card Kingdom, near mint, their price list as of .
Crowded Crypt 
Artifact · Rare · Aetherdrift Commander · #88
{T}: Add {B}.
Whenever a creature you control dies, put a corpse counter on this artifact.
{4}{B}{B}, {T}, Sacrifice this artifact: Create a 2/2 black Zombie creature token with decayed for each corpse counter on this artifact. (A creature with decayed can't block. When it attacks, sacrifice it at end of combat.)
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
3 printings · $1.29 to $3.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Aetherdrift Commander | 88 | Rare | $1.29 | — |
| Midnight Hunt Commander | 17 | Rare | $1.29 | — |
| Midnight Hunt Commander | 55 | Rare | $3.99 | — |
4 rulings from Wizards of the Coast
- 24 September 2021Decayed does not grant haste. Creatures with decayed that enter the battlefield during your turn may not attack until your next turn.
- 24 September 2021Once a creature with decayed attacks, it will be sacrificed at end of combat, even if it no longer has decayed at that time.
- 24 September 2021Decayed represents a static ability and a triggered ability. “Decayed” means “This creature can't block” and “When this creature attacks, sacrifice it at end of combat.”
- 24 September 2021Decayed does not create any attacking requirements. You may choose not to attack with a creature that has decayed.