Mikaeus, the Unhallowed + Canker Abomination

Mikaeus, the Unhallowed

Canker Abomination

How it works

1. Cast Canker Abomination by paying 2B/GB/G.
2. 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.
3. 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.
4. Repeat from step 2.