Cheapest priced copy (March of the Machine): $0.35 at Card Kingdom, near mint, their price list as of .
Wicked Slumber 
Instant · Uncommon · March of the Machine · #84
Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Tap up to two target creatures. Put a stun counter on either of them. Then put a stun counter on either of them. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| March of the Machine | 84 | Uncommon | $0.35 | $0.49 |
| The List | MOM-84 | Uncommon | $0.35 | — |
9 rulings from Wizards of the Coast
- 14 April 2023Wicked Slumber can target creatures that are already tapped.
- 14 April 2023If you choose two target creatures, but one of them is an illegal target as Wicked Slumber resolves, the illegal target will be unaffected. You'll put both stun counters on the remaining legal target. If both targets become illegal, Wicked Slumber won't resolve at all.
- 14 April 2023The two stun counters can end up on the same creature, or they can each end up on a different one of the target creatures.
- 12 January 2024Because convoke isn't an alternative cost, it can be used in conjunction with alternative costs.
- 12 January 2024When calculating a spell's total cost, include any alternative costs, additional costs, or anything else that increases or reduces the cost to cast the spell. Convoke applies after the total cost is calculated. Convoke doesn't change a spell's mana cost or mana value.
- 12 January 2024Tapping an untapped creature that's attacking or blocking to convoke a spell won't cause that creature to stop attacking or blocking.
- 12 January 2024Tapping a multicolored creature using convoke will pay for {1} or one mana of your choice of any of that creature's colors.
- 12 January 2024You can tap any untapped creature you control to convoke a spell, even one you haven't controlled continuously since the beginning of your most recent turn.
- 12 January 2024If a creature you control has a mana ability with {T} in the cost, activating that ability while casting a spell with convoke will result in the creature being tapped before you pay the spell's costs. You won't be able to tap it again for convoke. Similarly, if you sacrifice a creature to activate a mana ability while casting a spell with convoke, that creature won't be on the battlefield when you pay the spell's costs, so you won't be able to tap it for convoke.