Yarus, Roar of the Old Gods + Karlov Watchdog + Blim, Comedic Genius + Phantom Train

Yarus, Roar of the Old Gods

Karlov Watchdog

Blim, Comedic Genius

Phantom Train

How it works

1. Donate Karlov Watchdog to an opponent.
2. During the opponent's turn, activate Phantom Train by sacrificing a face-down creature you control.
3. When the creature dies, Yarus's second ability triggers, returning it from your graveyard to the battlefield face-down as a 2/2 creature, and then not turning it face-up due to Karlov Watchdog.
4. Resolve the Phantom Train ability.
5. Repeat from step 2.

This ingenious loop turns a discarded pet into an endless engine of rebirth and growth, orchestrated by Blim, Comedic Genius giving away pieces while Karlov Watchdog stays locked in enemy hands to sabotage their rules. Because Karlov Watchdog prevents permanents your opponents control from turning face up on your turn, it cleverly exploits Yarus, Roar of the Old Gods's resurrection trigger—when you sacrifice a face-down creature to fuel Phantom Train, Yarus returns it to the battlefield face-down, but the Watchdog stops it from flipping back up, leaving it primed to be sacrificed all over again. As Phantom Train feasts on these endless offerings, it piles on infinite +1/+1 counters and triggers, generating infinite sacrifice, death, and leave-the-battlefield loops.