Prowling Geistcatcher, Felidar Guardian, and Ashnod's Altar

Prerequisites

• Prowling Geistcatcher on the battlefield
• Felidar Guardian in hand
• Ashnod's Altar on the battlefield
• available

Steps

1. Cast Felidar Guardian by paying
2. Felidar Guardian enters the battlefield, triggering its ability, targeting Prowling Geistcatcher
3. Holding priority, activate Ashnod's Altar by sacrificing Felidar Guardian, adding
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

Results

• Infinite blinking
• Infinite colorless mana
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers