Flatline
Instant
Creatures your opponents control have base power and toughness 0/1 until end of turn.
- CMC
- 3
- Mana cost
- Color identity
- U
- Rarity
- rare
- Set
- Doctor Who
- Price
- $0.39
- EDHREC rank
- #6974
Flatline locks a player out of untapping their permanents for a full turn cycle — a punishing on-board stax effect stapled to a single black mana at instant speed. It's a niche card, but in decks like Toxrill, the Corrosive that already thrive on grinding opponents to a halt, that one mana buys an enormous tempo swing.
Best Commanders
Commanders with the highest synergy
Toxrill, the Corrosive
Toxrill, the Corrosive is the premier home for Flatline because both cards pursue the same gameplan: deny opponents the ability to act while slugs pile up and board states collapse under Toxrill's passive erosion.
Sephiroth, Planet's Heir
Sephiroth, Planet's Heir rewards controlling the board and pressuring specific opponents, and Flatline turns that pressure into a hard lock — keeping a key blocker or combo piece tapped at the critical moment.
Jenny Flint // Madame Vastra
Jenny Flint // Madame Vastra leans on tapping and untapping as a resource, and Flatline disrupts opposing permanents in the same idiom — preventing an opponent from untapping a critical threat before Vastra's investigation engine closes the game.
Ghyrson Starn, Kelermorph
Ghyrson Starn, Kelermorph pings creatures repeatedly, and Flatline keeps a dangerous blocker or activated-ability creature locked down for the turn, clearing the path for Ghyrson's damage-based removal to finish the job.
Format Analysis
Where it lives, where it can’t
| Format | Verdict |
|---|---|
| commander | legal |
| legacy | legal |
| modern | not legal |
| pioneer | not legal |
| standard | not legal |
| vintage | legal |
| pauper | not legal |
| oathbreaker | legal |
Flatline is a Commander card through and through — its value scales with the complexity and longevity of multiplayer games, where preventing a single opponent from untapping their permanents can swing a three-way board state decisively. In Legacy and Vintage, where it's technically legal, Flatline doesn't compete with the density of broken one-mana plays already available, and it sees essentially no play there. Oathbreaker offers another multiplayer home where the effect can matter, particularly in black stax builds looking for instant-speed disruption. Outside of Commander and Oathbreaker, the card simply doesn't exist competitively.
Key Combos
Combo lines featuring this card
Price Context
Current price
$0.39 bulk tier
At $0.39, Flatline is firmly bulk — easy to acquire as a throw-in or cheap pickup for any black stax build. Its niche role keeps demand low, so the price is stable and unlikely to spike absent a breakout Commander combo.
Explore
Sources
Mentioned
- Toxrill, the Corrosive
- Sephiroth, Planet's Heir
- Jenny Flint // Madame Vastra
- Ghyrson Starn, Kelermorph
Updated . Data from Scryfall, EDHREC, and Commander Spellbook.