Preston, the Vanisher + Delney, Streetwise Lookout + Sefris of the Hidden Ways + Altar of Dementia + Avenging Hunter
Preston, the Vanisher
Delney, Streetwise Lookout
Sefris of the Hidden Ways
Altar of Dementia
Avenging Hunter
Infinite artifact ETBInfinite artifact LTBInfinite artifact sacrifice triggersInfinite artifact tokensInfinite +1/+1 counters on creatures you controlInfinite creature ETBInfinite creature LTBInfinite Treasure tokensInfinite card drawInfinite colored manaInfinite creature tokensInfinite death triggersInfinite draw triggersInfinite millInfinite creature sacrifice triggersInfinite self-millNear-infinite lifelossPut all basic lands from your library into your handPut all creature cards from your library onto the battlefieldReturn most creature cards from your graveyard onto the battlefield
How it works
Complete a dungeon.
Sefris' second ability triggers twice due to Delney.
Resolve the first trigger, returning up to one other creature from your graveyard to the battlefield.
Resolve the second trigger, returning Avenging Hunter from your graveyard onto the battlefield.
When Avenging Hunter enters, it triggers once and Preston triggers twice due to Delney.
Holding priority, activate Altar of Dementia by sacrificing Avenging Hunter.
Resolve a Preston trigger, creating a token copy of Avenging Hunter that is a 0/1 Illusion.
When the Avenging Hunter token enters, it triggers twice due to Delney.
Resolve the Avenging Hunter token triggers, venturing into Undercity twice.
Resolve the second Preston trigger from step 5, creating a token copy of Avenging Hunter that is a 0/1 Illusion.
Repeat steps 8 and 9 one additional time.
Resolve the Avenging Hunter trigger from step 5, venturing into Undercity and completing Undercity.