Cheapest priced copy (Bloomburrow): $13.99 at Card Kingdom, near mint, out of stock, their price list as of .
Rottenmouth Viper 
Creature — Elemental Snake · 6/6 · Mythic · Bloomburrow · #290
As an additional cost to cast this spell, you may sacrifice any number of nonland permanents. This spell costs {1} less to cast for each permanent sacrificed this way.
Whenever this creature enters or attacks, put a blight counter on it. Then for each blight counter on it, each opponent loses 4 life unless that player sacrifices a nonland permanent of their choice or discards a card.
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
4 printings · $11.99 to $32.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Bloomburrow | 107 | Mythic | $13.99Out of stock | $11.99Out of stock |
| Bloomburrow | 290 | Mythic | $20.99 | $32.99 |
| Bloomburrow Promos | 107p | Mythic | $13.99Out of stock | $27.99 |
| Bloomburrow Promos | 107s | Mythic | — | $16.99 |
4 rulings from Wizards of the Coast
- 26 July 2024While resolving Rottenmouth Viper’s triggered ability, your opponent chooses a card to be discarded without revealing it, chooses a nonland permanent to be sacrificed, or chooses to do neither. Cards or permanents they’ve chosen previously during this process can’t be chosen again. Then that player repeats that process if it hasn’t yet been done once for each blight counter on Rottenmouth Viper. Finally, that player discards the chosen cards, sacrifices the chosen permanents, and loses 4 life the appropriate number of times.
- 26 July 2024In a multiplayer game, each opponent in turn order makes all of their choices, then all of the actions occur simultaneously. Opponents will know what choices opponents earlier in turn order made, although cards chosen to be discarded this way won’t be revealed until they’re discarded at the end of the process.
- 26 July 2024If Rottenmouth Viper leaves the battlefield before its triggered ability resolves, use the number of blight counters that were on it as it last existed on the battlefield to determine how many times each opponent must make the listed choice.
- 26 July 2024An opponent can always choose not to sacrifice a nonland permanent or discard a card (and therefore lose 4 life) even if they have cards in their hand or nonland permanents on the battlefield.