Missy + Skirk Alarmist + Intruder Alarm + Altar of Dementia

Missy

Skirk Alarmist

Intruder Alarm

Altar of Dementia

How it works

1. Activate Altar of Dementia by sacrificing another nontoken nonartifact creature When the creature dies, Missy's first ability triggers, returning the creature from your graveyard to the battlefield face down as a 2/2 Cyberman artifact creature.
2. When the creature enters the battlefield, Intruder Alarm triggers, untapping all creatures.
3. Resolve the Altar of Dementia ability from step 1, causing target player to mill cards equal to the sacrificed creature's power.
4. Activate Skirk Alarmist by tapping it, turning the creature face up.
5. Repeat.

This loop turns a simple graveyard recursion trick into an endless mill engine by exploiting the constant influx of fresh entries and exits. You kick things off by sacrificing a creature to Altar of Dementia, which immediately triggers Missy to rescue it from the graveyard and sneak it right back onto the battlefield as a face-down 2/2 Cyberman artifact creature. That new entry instantly wakes up Intruder Alarm, which untaps all your creatures—including Skirk Alarmist, who is then tapped to flip the Cyberman face up. Because Skirk Alarmist and Altar of Dementia are ready to go again, you can feed the creature right back into the Altar to mill your opponent out while repeating the whole cycle infinitely.