Marath, Will of the Wild + Mana Echoes + Hardened Scales

Marath, Will of the Wild

Mana Echoes

Hardened Scales

How it works

1. Activate Marath by paying 1 and removing a +1/+1 counter from it, creating a 1/1 Elemental creture token.
2. The Elemental enters the battlefield, triggering Mana Echoes, adding C for each Elemental you control.
3. Activate Marath by paying 1 and removing a +1/+1 counter from it, putting two +1/+1 counters on it.
4. Repeat.
5. Once you have infinite C, you may repeat step 3 to give Marath infinite +1/+1 counters, then use them to deal infinite damage to any target(s).