Mikaeus, the Unhallowed + Blasting Station + Putrid Goblin

Mikaeus, the Unhallowed

Blasting Station

Putrid Goblin

How it works

1. Activate Blasting Station by tapping it and sacrificing Putrid Goblin.
2. When Putrid Goblin dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. When Putrid Goblin enters, Blasting Station triggers, untapping Blasting Station.
4. Resolve the Blasting Station ability from step 1.
5. Activate Blasting Station by tapping it and sacrificing Putrid Goblin.
6. When Putrid Goblin dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
7. When Putrid Goblin enters, Blasting Station triggers, untapping Blasting Station.
8. Resolve the Blasting Station ability from step 5.
9. Repeat.

This loop relies on the brilliant counterplay between Putrid Goblin's native persist ability and the undying granted to it by Mikaeus, the Unhallowed. When you sacrifice the Goblin to Blasting Station, persist brings it back with a -1/-1 counter, but because Mikaeus also provides a +1/+1 counter when it returns via undying, the two opposing counters immediately annihilate each other through state-based actions. This leaves the creature completely clean of counters so the cycle can repeat indefinitely, letting Blasting Station endlessly untap itself to ping your opponents to death.