Prowling Geistcatcher, Kiki-Jiki, Mirror Breaker, and Phyrexian Altar

Prerequisites

• Prowling Geistcatcher on the battlefield
• Kiki-Jiki, Mirror Breaker on the battlefield
• Phyrexian Altar on the battlefield

Steps

1. Activate Kiki-Jiki by tapping it, creating a token copy of Prowling Geistcatcher with haste
2. Activate Phyrexian Altar by sacrificing Kiki-Jiki, adding one mana of any color
3. When Kiki-Jiki dies, the nontoken and token Prowling Geistcatcher's first abilities trigger
4. Resolve the token Prowling Geistcatcher's trigger, exiling Kiki-Jiki from your graveyard
5. Resolve the nontoken Prowling Geistcatcher's trigger, doing nothing
6. Activate Phyrexian Altar by sacrificing the Prowling Geistcatcher token, adding one mana of any color
7. When the token Prowling Geistcatcher dies, its second ability and the nontoken Prowling Geistcatcher's first ability triggers
8. Resolve the nontoken Prowling Geistcatcher trigger, putting a +1/+1 counter on it
9. Resolve the token Prowling Geistcatcher trigger, returning Kiki-Jiki from exile to the battlefield
10. Repeat

Results

• Infinite +1/+1 counters on Prowling Geistcatcher
• Infinite colored mana
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers