Felidar Guardian + Vesperlark + Phyrexian Altar

Felidar Guardian

Vesperlark

Phyrexian Altar

How it works

1. Cast Felidar Guardian by paying 3.
2. When Felidar Guardian enters the battlefield, it triggers, targeting Vesperlark.
3. Holding priority, activate Phyrexian Altar by sacrificing Felidar Guardian.
4. Resolve the Felidar Guardian trigger, blinking Vesperlark.
5. When Vesperlark leaves the battlefield, it triggers, returning Felidar Guardian from your graveyard to the battlefield.
6. Repeat from step 2.

This elegant loop turns a modest cat and an elemental into a self-sustaining engine using Phyrexian Altar as both the catalyst and the outlet. When you cast Felidar Guardian, its entrance triggers to blink Vesperlark, which immediately leaves the battlefield and triggers its own ability to fish the Guardian right back out of your graveyard. Meanwhile, sacrificing Felidar Guardian to Phyrexian Altar along the way provides a steady stream of colored mana to fund future casts while generating infinite sacrifice and death triggers.