Mikaeus, the Unhallowed, Murderous Redcap, and Phyrexian Altar

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Murderous Redcap on the battlefield
• Phyrexian Altar on the battlefield

Steps

1. Sacrifice Murderous Redcap to Phyrexian Altar to add a mana of any color
2. Murderous Redcap's persist triggers, returning it from your graveyard to the battlefield with a -1/-1 counter
3. Murderous Redcap triggers, dealing damage equal to it's power to any target
4. Sacrifice Murderous Redcap to Phyrexian Altar to add a mana of any color
5. Murderous Redcap's undying triggers, returning it from your graveyard to the battlefield with a +1/+1 counter
6. Murderous Redcap triggers, dealing damage equal to it's power to any target
7. Repeat

Results

• Infinite colored mana
• Infinite damage
• Infinite death triggers
• Infinite ETB
• Infinite LTB