Prowling Geistcatcher + Felidar Guardian + Phyrexian Altar

Prowling Geistcatcher

Felidar Guardian

Phyrexian Altar

How it works

1. Cast Felidar Guardian by paying 3.
2. Felidar Guardian enters the battlefield, triggering its ability, targeting Prowling Geistcatcher.
3. Holding priority, activate Phyrexian Altar by sacrificing Felidar Guardian, adding one mana of any color.
4. Prowling Geistcatcher triggers, exiling Felidar Guardian from your graveyard.
5. Resolve the Felidar Guardian trigger from 2, blinking Prowling Geistcatcher.
6. Prowling Geistcatcher leaves the battlefield, returning Felidar Guardian from exile to the battlefield.
7. Repeat from step 2.