Mikaeus, the Unhallowed + Canker Abomination + Blasting Station

Mikaeus, the Unhallowed

Canker Abomination

Blasting Station

How it works

1. Activate Blasting Station by tapping it and 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 and Blasting Station trigger.
4. Resolve the Blasting Station trigger, untapping it.
5. Resolve the Canker Abomination trigger, putting a number of -1/-1 counters on it equal to the number of creatures an opponent controls.
6. 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 5 infinitely.
7. Otherwise, resolve the Blasting Station ability, and repeat from step 1.