Mikaeus, the Unhallowed + Blasting Station + Moonshadow

Mikaeus, the Unhallowed

Blasting Station

Moonshadow

How it works

1. Activate Blasting Station by tapping it and sacrificing Moonshadow.
2. When Moonshadow dies, its undying ability triggers, returning it from your graveyard to the battlefield without a +1/+1 counter on it due to its replacement effect.
3. When Moonshadow enters, Blasting Station triggers, untapping Blasting Station.
4. Resolve the Blasting Station ability from step 1
5. Repeat.