Mikaeus, the Unhallowed + Canker Abomination + Phantom Train

Mikaeus, the Unhallowed

Canker Abomination

Phantom Train

How it works

1. Activate Phantom Train by sacrificing Canker Abomination.
2. When Canker Abomination dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
3. When Canker Abomination enters the battlefield, it triggers, putting a number of -1/-1 counters on it equal to the number of creatures an opponent controls.
4. If the opponent had seven or more creatures, Canker Abomination will die as a state-based action due to having 0 or less toughness. If this occurs, repeat steps 2 through 4 infinitely.
5. Otherwise, resolve the Phantom Train ability, and repeat from step 1.
6. Cast Canker Abomination by paying 2B/GB/G.
7. When Canker Abomination enters the battlefield, it triggers, putting a number of -1/-1 counters on it equal to the number of creatures an opponent controls.
8. Canker Abomination dies as a state-based action due to having 0 or less toughness, triggering its undying ability, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
9. Repeat from step 2.

This clever loop relies on Mikaeus, the Unhallowed to grant undying to your other non-Human creatures, turning Canker Abomination into an immortal engine whenever an opponent controls enough creatures to immediately zero out its toughness. By feeding Canker Abomination to Phantom Train, you trigger its death and subsequent return with a +1/+1 counter, which gets immediately wiped away by the influx of -1/-1 counters when it re-enters the battlefield. This interaction allows you to endlessly sacrifice and recur the Abomination, generating infinite sacrifice, death, and entry triggers to fuel your victory.