Blasting Station + Thran Vigil + Grazing Kelpie

Blasting Station

Thran Vigil

Grazing Kelpie

How it works

1. Activate Blasting Station by tapping it and sacrificing Grazing Kelpie.
2. When Grazing Kelpie dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Thran Vigil and Blasting Station trigger.
4. Resolve the Thran Vigil trigger, putting a +1/+1 counter on Grazing Kelpie.
5. Resolve the Blasting Station trigger, untapping it.
6. Resolve the Blasting Station ability from step 1.
7. Repeat.