Ashnod's Altar + Scurry Oak + Yuna, Grand Summoner

Ashnod's Altar

Scurry Oak

Yuna, Grand Summoner

How it works

1. Cast Scurry Oak by paying its mana cost.
2. When Scurry Oak enters, the effect that adds +1/+1 counters to entering creatures triggers or applies its replacement effect, putting at least one +1/+1 counter on Scurry Oak.
3. Scurry Oak triggers, creating a creature token.
4. When the creature token enters, that same effect causes you to place at least one +1/+1 counter on it.
5. Activate Ashnod's Altar by sacrificing the creature token, adding CC.
6. When the creature token dies, Yuna triggers, putting at least one +1/+1 counter on Scurry Oak
7. Repeat steps 3 and 4 once.
8. Repeat from step 5.