Shalai, Voice of Plenty + Crystalline Crawler + Cryptic Trilobite + Branching Evolution

Shalai, Voice of Plenty

Crystalline Crawler

Cryptic Trilobite

Branching Evolution

How it works

1. Activate Shalai by paying 4, putting two +1/+1 counters on each creature you control.
2. Activate Cryptic Trilobite's first ability twice by removing two +1/+1 counters from it, adding CCCC that can only be spent to activate abilities.
3. Activate Crystalline Crawler's first ability twice by removing two +1/+1 counters from it, adding .
4. Repeat.