Prowling Geistcatcher + Kiki-Jiki, Mirror Breaker + Altar of Dementia

Prowling Geistcatcher

Kiki-Jiki, Mirror Breaker

Altar of Dementia

How it works

1. Activate Kiki-Jiki by tapping it, creating a token copy of Prowling Geistcatcher with haste.
2. Activate Altar of Dementia by sacrificing Kiki-Jiki.
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. Resolve the Altar of Dementia ability, causing target player to mill cards equal to Kiki-Jiki's power.
7. Activate Altar of Dementia by sacrificing the Prowling Geistcatcher token.
8. When the token Prowling Geistcatcher dies, its second ability and the nontoken Prowling Geistcatcher's first ability triggers.
9. Resolve the nontoken Prowling Geistcatcher trigger, putting a +1/+1 counter on it.
10. Resolve the token Prowling Geistcatcher trigger, returning Kiki-Jiki from exile to the battlefield.
11. Resolve the Altar of Dementia ability, causing target player to mill cards equal to the token Prowling Geistcatcher's power.
12. Repeat.

This fascinating loop relies on a clever interplay of duplication, sacrifice, and recursive exile to mill out your opponents completely. Kiki-Jiki, Mirror Breaker kicks things off by generating a token copy of Prowling Geistcatcher, which then allows you to sacrifice the original Kiki-Jiki to Altar of Dementia without losing it for good; the token Prowling Geistcatcher safely catches Kiki-Jiki in exile rather than letting it rest in the graveyard. When you subsequently sacrifice the Prowling Geistcatcher token to Altar of Dementia, its departure triggers the return of Kiki-Jiki while placing a permanent +1/+1 counter on your original Prowling Geistcatcher. Repeating this sequence endlessly lets you mill target players completely while pumping your board with infinite counters and triggers.