Infinite colored manaInfinite death triggersInfinite creature ETBInfinite creature LTBInfinite mana creatures you control can produceInfinite creature sacrifice triggersInfinite untap of creatures
How it works
Activate Phyrexian Altar by sacrificing Ashcloud Phoenix, adding one mana of any color.
When Ashcloud Phoenix dies, it triggers, returning itself from your graveyard to the battlefield face down.
When Ashcloud Phoenix enters the battlefield, Intruder Alarm triggers, untapping all creatures.
Activate Skirk Alarmist by tapping it, turning Ashcloud Phoenix face up.
Repeat.
This brilliant loop centers on Ashcloud Phoenix continuously cycling between the graveyard, the battlefield, and face-down state, fueling Phyrexian Altar for infinite colored mana and sacrificing it over and over. Every time the Phoenix re-enters the battlefield face down, Intruder Alarm triggers to untap all your creatures, immediately readying Skirk Alarmist to flip the Phoenix back face up. Skirk Alarmist's delayed sacrifice trigger is entirely bypassed because the Phoenix leaves play the moment you sacrifice it back to the Altar, keeping the engine running endlessly.