Cheapest priced copy (Duskmourn: House of Horror Commander): $1.29 at Card Kingdom, near mint, their price list as of .
Fear of Sleep Paralysis 
Enchantment Creature — Nightmare · 6/6 · Rare · Duskmourn: House of Horror Commander · #43
Flying
Eerie — Whenever this creature or another enchantment you control enters and whenever you fully unlock a Room, tap up to one target creature and put a stun counter on it.
Stun counters can't be removed from permanents your opponents control. (They won't untap if they have stun counters.)
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $1.29 to $2.29 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Duskmourn: House of Horror Commander | 12 | Rare | $1.29 | — |
| Duskmourn: House of Horror Commander | 43 | Rare | $2.29 | — |
5 rulings from Wizards of the Coast
- 20 September 2024While you control Fear of Sleep Paralysis, if a permanent an opponent controls with a stun counter would untap, it doesn't untap and the stun counter isn't removed.
- 20 September 2024If a permanent with an eerie ability enters at the same time as one or more enchantments, its ability will trigger for each of those enchantments.
- 20 September 2024An ability that triggers "whenever you fully unlock a Room" triggers when a door becomes unlocked and the other door of that Room is already unlocked, or when both doors of that Room become unlocked simultaneously.
- 20 September 2024While you control Fear of Sleep Paralysis, opponents can't use tapped permanents with stun counters on them to pay costs that include untapping a permanent. This includes costs that use the {Q} (untap) symbol.
- 20 September 2024If an ability tries to move a stun counter from a permanent an opponent controls to another permanent while you control Fear of Sleep Paralysis, that counter won't move. No stun counters will be removed from or put onto anything.