Prerequisites
- Tainted Observer on the battlefield
- Ashnod's Altar on the battlefield
- Herd Baloth on the battlefield
- You have a way to cause a creature to enter the battlefield under your control
- Herd Baloth has at least one +1/+1 counter on it
Steps
- Cause a creature to enter the battlefield under your control
- When the creature enters the battlefield, Tainted Observer triggers
- Holding priority, activate Ashnod's Altar by sacrificing the creature, adding
- Resolve the Tainted Observer trigger, causing you to pay to put a +1/+1 counter on Herd Baloth
- Herd Baloth triggers, creating a 4/4 Beast creature token
- Repeat from step 2
Results
- Infinite +1/+1 counters on Herd Baloth
- Infinite death triggers
- Infinite ETB
- Infinite LTB
- Infinite proliferate
- Infinite sacrifice triggers
Required Cards 3
Tainted Observer
Creature — Phyrexian Bird
Herd Baloth
Creature — Beast