First printed in Phyrexia: All Will Be One (2023)
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 
. If you do, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
MTGO price: 0.003 TIX, the cheapest non-foil print (average sell price on GoatBots, 28 Oct 2026).
In Limited on MTG Arena
Win rates in Arena drafts and sealed, retrieved from 17Lands (CC BY 4.0).
| Set | GIH WR | vs set | IWD | Games |
|---|---|---|---|---|
| Phyrexia: All Will Be One (ONE), Premier Draft | 50.6% | -4.1 | +2.2 | 9349 |
| Phyrexia: All Will Be One (ONE), Sealed | 52.4% | -3.9 | +2.4 | 1021 |
- GIH WR
- win rate of the games in which the card was in the opening hand or drawn
- vs set
- points above or below the average win rate of all decks in the set
- IWD
- improvement when drawn: GIH WR minus the win rate when the card stayed in the library
- Games
- games in which the card was seen
Combos
22 combos from Commander Spellbook, the most popular first.
- Infinite death triggers, Infinite creature ETB…: Ashnod's Altar + Tainted Observer + Venser, Corpse Puppet
- Infinite +1/+1 counters on a creature, Infinite death triggers…: Ashnod's Altar + Scurry Oak + Tainted Observer
- Infinite death triggers, Infinite creature ETB…: Ashnod's Altar + Sporoloth Ancient + Tainted Observer + Tekuthal, Inquiry Dominus
- Infinite colorless mana, Infinite creature tokens…: Ashnod's Altar + Doubling Season + Sporoloth Ancient + Tainted Observer
- Infinite death triggers, Infinite creature ETB…: Adrix and Nev, Twincasters + Ashnod's Altar + Sporoloth Ancient + Tainted Observer
- Infinite death triggers, Infinite creature ETB…: Ashnod's Altar + Parallel Lives + Sporoloth Ancient + Tainted Observer
- Infinite death triggers, Infinite creature ETB…: Ashnod's Altar + Pir, Imaginative Rascal + Sporoloth Ancient + Tainted Observer
- Infinite death triggers, Infinite creature ETB…: Ashnod's Altar + Primal Vigor + Sporoloth Ancient + Tainted Observer
- Infinite death triggers, Infinite creature ETB…: Ashnod's Altar + Saproling Burst + Tainted Observer
- Infinite death triggers, Infinite creature ETB…: Krark-Clan Ironworks + Tainted Observer + Venser, Corpse Puppet
Legality
Constructed
- Standard Not legal
- Pioneer Legal
- Modern Legal
- Legacy Legal
- Vintage Legal
- Pauper Not legal
- Future Standard Not legal
- Historic Legal
- Timeless Legal
- Alchemy Not legal
- Penny Dreadful Not legal
- Premodern Not legal
- Old School 93/94 Not legal
Singleton
- Gladiator Legal
Commander formats
- Commander Legal
- Duel Commander Legal
- Pauper Commander Not legal
- PreDH Not legal
- Tiny Leaders Legal
- Oathbreaker Legal
- Brawl Legal
- Standard Brawl Not legal
- Competitive Brawl Legal