Cheapest priced copy (Guilds of Ravnica): $0.35 at Card Kingdom, near mint, their price list as of .
Mephitic Vapors 
Sorcery · Common · Ravnica Remastered · #85
All creatures get -1/-1 until end of turn.
Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
3 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Guilds of Ravnica | 76 | Common | $0.35 | $0.49 |
| The List | GRN-76 | Common | $0.35 | — |
| Ravnica Remastered | 85 | Common | $0.35 | $0.49 |
4 rulings from Wizards of the Coast
- 5 October 2018Mephitic Vapors affects only creatures on the battlefield at the time it resolves. Creatures that enter the battlefield later in the turn won't get -1/-1.
- 5 October 2018Creatures that are going to die after getting -1/-1 will still be on the battlefield while you surveil. They won't be put into their owners' graveyards until after Mephitic Vapors is entirely finished resolving. If any of their abilities trigger on surveilling, those abilities will trigger but won't resolve until after the creatures have left the battlefield.
- 12 January 2024When you surveil, you may put all the cards you look at back on top of your library, you may put all of those cards into your graveyard, or you may put some of those cards on top and the rest of them into your graveyard.
- 12 January 2024You perform the actions stated on a card in sequence. For some spells and abilities, you'll surveil last. For others, you'll surveil and then perform other actions.