Mortuary + Experimental Frenzy + Priest of Urabrask + Phyrexian Altar

Mortuary

Experimental Frenzy

Priest of Urabrask

Phyrexian Altar

How it works

1. Activate Phyrexian Altar by sacrificing Priest of Urabrask, adding .
2. When Priest of Urabrask dies, Mortuary triggers, putting Priest of Urabrask on top of your library from your graveyard.
3. Cast Priest of Urabrask from the top of your library by paying 2.
4. When Priest of Urabrask enters the battlefield, it triggers, adding .
5. Repeat.

This loop lets you churn through your deck by turning the top of your library into an active recycling zone. With Experimental Frenzy granting you the ability to cast spells directly from the top of your library, Priest of Urabrask can be repeatedly deployed, sacrificed to Phyrexian Altar for mana, and immediately redirected back to the top of your library via Mortuary's triggered ability. Because the red mana generated by the priest comfortably outpaces the casting cost to replay it from the library, you generate an infinite loop of sacrifices and enters-the-battlefield triggers while swimming in limitless colored mana.