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Tainted Observer

Creature — Phyrexian Bird

Flying
Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Whenever another creature you control enters, you may pay {2}. If you do, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

CMC
3
Mana cost
{1}{G}{U}
Color identity
GU
Rarity
uncommon
Set
Phyrexia: All Will Be One
Price
$0.28
EDHREC rank
#6622
Buy on TCGplayer
Tainted Observer card art
Tainted Observer puts a proliferate trigger on every creature that enters with counters, turning each new threat into a board-wide upgrade — and in the right shell, that's happening multiple times per turn. The two-mana body is irrelevant; you're paying for the effect, and commanders like Venser, Corpse Puppet and Ezuri, Stalker of Spheres make that effect absurd.

Best Commanders

Commanders with the highest synergy

01
Ezuri, Stalker of Spheres

Ezuri, Stalker of Spheres

62.8% of decks · synergy 0.61

Ezuri, Stalker of Spheres draws a card whenever you proliferate, so Tainted Observer converts every modular trigger, every oil counter, every evolve entry into card advantage — the two engines are inseparable.

02
Ezuri, Claw of Progress

Ezuri, Claw of Progress

18.4% of decks · synergy 0.17

Tainted Observer enters as a 1/1 with an oil counter and immediately triggers Ezuri, Claw of Progress, then each subsequent evolved creature proliferates those experience counters further, compressing two axes of growth into one card.

03
Xavier Sal, Infested Captain

Xavier Sal, Infested Captain

13.4% of decks · synergy 0.13

Xavier Sal, Infested Captain cares about toxic and poison, and Tainted Observer's proliferate on each counter-laden entry accelerates opponent poison totals without needing to connect in combat.

04
Atraxa, Praetors' Voice

Atraxa, Praetors' Voice

23.1% of decks · synergy 0.09

Atraxa, Praetors' Voice already proliferates at end step, and Tainted Observer adds mid-turn proliferation on every creature with a counter — the redundancy is exactly what Atraxa decks are hunting.

Format Analysis

Where it lives, where it can’t

FormatVerdict
commander legal
legacy legal
modern legal
pioneer legal
standard not legal
vintage legal
pauper not legal
oathbreaker legal

Commander is the only format where Tainted Observer is genuinely powerful — the effect scales with the number of creatures entering with counters, and 100-card singleton decks built around proliferate, +1/+1 counters, or poison easily manufacture the density it needs. In competitive formats like Modern and Legacy, a 1/1 for two that requires setup to generate value isn't close to playable; faster linear strategies don't give it time to matter. Pioneer is the same story — the creature base and counter synergies that would enable Tainted Observer are softer there, and three mana for meaningful value is a steep ask. Treat it as a Commander-only card that happens to be legal elsewhere.

Key Combos

Combo lines featuring this card

Price Context

Current price

$0.28 bulk tier

At $0.28, Tainted Observer is deep bulk — easy to pick up in any common box or as a throw-in. The price reflects limited competitive demand, not the card's actual ceiling in dedicated counter and proliferate decks, so stock up freely.

Explore

Sources

Mentioned

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Updated . Data from Scryfall, EDHREC, and Commander Spellbook.