Bloodied Ghost + Mikaeus, the Unhallowed + Phyrexian Altar

WB identity

Commander legal

The 3 combo pieces

• Bloodied Ghost
• Mikaeus, the Unhallowed
• Phyrexian Altar

How to execute it

1. Activate Phyrexian Altar by sacrifiicing Bloodied Ghost.
2. When Bloodied Ghost dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it. When it enters, Bloodied Ghost will put a -1/-1 counter on itself, removing the +1/+1 counter.
3. Repeat.

What the combo produces

• Infinite colored mana
• Infinite creature LTB
• Infinite death triggers
• Infinite ETB
• Infinite sacrifice triggers