Scarecrone + Thornbite Staff + Cathodion + Krark-Clan Ironworks

Scarecrone

Thornbite Staff

Cathodion

Krark-Clan Ironworks

How it works

1. Activate Krark-Clan Ironworks by sacrificing Cathodion, adding CC.
2. Cathodion dies, triggering itself and Scarecrone.
3. Resolve the Cathodion trigger, adding CCC.
4. Resolve the Scarecrone trigger, untapping it.
5. Activate Scarecrone's second ability by paying 4 and tapping it, returning Cathodion from your graveyard to the battlefield.
6. Repeat.