The Ooze + Basking Broodscale + Bloodspore Thrinax

The Ooze

Basking Broodscale

Bloodspore Thrinax

How it works

1. Cast Basking Broodscale by paying 1.
2. When Basking Broodscale enters with a +1/+1 counter on it due to Bloodspore Thrinax, it triggers, creating a 0/1 Eldrazi Spawn creature token that'll also enter with a +1/+1 counter on it.
3. Activate the Eldrazi Spawn by sacrificing it, adding C.
4. When the Eldrazi Spawn dies, The Ooze triggers, creating a Mutagen token.
5. Activate the Mutagen by paying 1, tapping and sacrificing it, putting a +1/+1 counter on Basking Broodscale.
6. Basking Broodscale triggers, creating a 0/1 Eldrazi Spawn creature token that'll enter with a +1/+1 counter on it.
7. Repeat from step 3.