Cheapest priced copy (Forgotten Realms Commander): $0.49 at Card Kingdom, near mint, their price list as of .
Theater of Horrors 
Enchantment · Rare · Duskmourn: House of Horror Commander · #236
At the beginning of your upkeep, exile the top card of your library.
During your turn, if an opponent lost life this turn, you may play lands and cast spells from among cards exiled with this enchantment.
{3}{R}: This enchantment deals 1 damage to target opponent or planeswalker.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
5 printings · $0.49 to $1.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Forgotten Realms Commander | 194 | Rare | $0.49 | — |
| Duskmourn: House of Horror Commander | 236 | Rare | $0.49 | — |
| Ravnica Allegiance Promos | 213s | Rare | — | $1.49 |
| Ravnica Allegiance | 213 | Rare | $0.49 | $1.99 |
| Starter Commander Decks | 250 | Rare | $0.49 | — |
4 rulings from Wizards of the Coast
- 25 January 2019Theater of Horrors doesn't change when you can play the exiled cards during your turn. For example, if you exile a sorcery card, you can cast it only during your main phase when the stack is empty. If you exile a land card, you can play it only during your main phase and only if you have an available land play remaining.
- 25 January 2019Casting an exiled card causes it to leave exile. You can't cast it multiple times.
- 25 January 2019Damage dealt to a player causes that player to lose that much life.
- 25 January 2019In a multiplayer game, if an opponent loses life during your turn and then leaves the game, you can play cards exiled with Theater of Horrors.