Grim Poppet + Mikaeus, the Unhallowed + Phyrexian Altar

B identity

Commander legal

The 3 combo pieces

• Grim Poppet
• Mikaeus, the Unhallowed
• Phyrexian Altar

How to execute it

1. Activate Phyrexian Altar by sacrificing Grim Poppet.
2. When Grim Poppet dies, its undying ability triggers, returning it from your graveyard to the battlefield without a +1/+1 counter on it due to its replacement effect.
3. Repeat.

What the combo produces

• Infinite -1/-1 counters
• Infinite colored mana
• Infinite creature LTB
• Infinite death triggers
• Infinite ETB
• Infinite sacrifice triggers