Koll, the Forgemaster + Dissection Tools + Shuko + Su-Chi

Koll, the Forgemaster

Dissection Tools

Shuko

Su-Chi

How it works

1. Activate Shuko's equip ability by paying 0, attaching it to Su-Chi.
2. Activate Dissection Tools by sacrificing Su-Chi, targeting Koll.
3. When Su-Chi dies, it and Koll trigger.
4. Resolve the Su-Chi trigger, adding CCCC.
5. Resolve the Koll trigger, returning it from your graveyard to your hand.
6. Resolve the Dissection Tools ability, attaching it to Koll.
7. Cast Su-Chi by paying its mana cost.
8. Repeat.