Basalt Monolith + Heartstone + Tezzeret, Betrayer of Flesh

Basalt Monolith

Heartstone

Tezzeret, Betrayer of Flesh

How it works

1. Activate Tezzeret's second loyalty ability by removing two loyalty counters from it, causing Basalt Monolith to become an artifact creature.
2. Activate Basalt Monolith's first ability by tapping it, adding CCC.
3. Activate Basalt Monolith's second ability by paying 2, untapping it.
4. Repeat from step 2.