Chatterfang, Squirrel General + Myr Propagator + Ashnod's Altar + Lightning Greaves

Chatterfang, Squirrel General

Myr Propagator

Ashnod's Altar

Lightning Greaves

How it works

1. Activate Lightning Greaves' equip ability by paying 0, attaching it to Myr Propagator.
2. Activate Myr Propagator by paying 3 and tapping it, creating a token copy of itself and a 1/1 Squirrel creature token.
3. Activate Ashnod's Altar twice by sacrificing the tapped Myr Propagator and the Squirrel, adding CCCC.
4. Repeat.
5. Once you have infinite mana, you may forego sacrificing the Myr Propagator and/or Squirrel tokens.

This loop spins up a self-sustaining engine by letting Myr Propagator clone itself while Chatterfang, Squirrel General doubles every single token creation with an extra cohort of 1/1 green Squirrels. You can feed those newly minted Squirrels and the original Myr Propagator right into Ashnod's Altar to easily generate the four colorless mana needed to fund the next activation cycle. Meanwhile, Lightning Greaves steps in to grant shroud and haste to the Myr Propagator, protecting it from targeted interaction and allowing it to activate immediately without waiting for summoning sickness.