The Ooze + Basking Broodscale + Grumgully, the Generous

The Ooze

Basking Broodscale

Grumgully, the Generous

How it works

1. Cast Basking Broodscale by paying 1.
2. When Basking Broodscale enters with a +1/+1 counter on it due to Grumgully, 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.

This ingenious loop transforms the simple act of placing counters into a self-sustaining engine, with Grumgully, the Generous ensuring that Basking Broodscale instantly triggers its spawn-creation ability the moment it enters the battlefield. Every time you sacrifice the resulting Eldrazi Spawn for mana, The Ooze catches the dying token's departure and rewards you with a Mutagen token. Sapping that Mutagen token to add a +1/+1 counter back onto Basking Broodscale restarts the entire chain, giving you an infinite supply of artifact and creature triggers to fuel whatever victory you desire.