Skeleton Ship + Intruder Alarm + Geralf's Mindcrusher + Carrion Feeder

Skeleton Ship

Intruder Alarm

Geralf's Mindcrusher

Carrion Feeder

How it works

1. Activate Carrion Feeder by sacrificing Geralf's Mindcrusher.
2. Geralf's Mindcrusher dies, triggering its undying ability, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
3. Geralf's Mindcrusher enters the battlefield, triggering itself and Intruder Alarm.
4. Resolve the Geralf's Mindcrusher trigger, causing target player to mill five cards.
5. Resolve the Intruder Alarm trigger, untapping all creatures.
6. Resolve the Carrion Feeder ability from step 1, putting a +1/+1 counter on it.
7. Activate Skeleton Ship by tapping it, putting a -1/-1 counter on Geralf's Mindcrusher.
8. Repeat.

This cunning loop turns the steady pressure of Skeleton Ship into a relentless engine of decay, using its ability to place a -1/-1 counter on Geralf's Mindcrusher to wipe away the +1/+1 counter it received from undying. Once the Mindcrusher is sacrificed to Carrion Feeder, it returns to the battlefield anew, which in turn triggers Intruder Alarm to untap everything—including Skeleton Ship—so you can repeat the process. Meanwhile, each iteration mills your target further and feeds Carrion Feeder's growing power, culminating in an overwhelming advantage on the board.