Alesha, Who Smiles at Death + Crystalline Crawler + Aggravated Assault + Arcbound Overseer + Umbral Collar Zealot

Alesha, Who Smiles at Death

Crystalline Crawler

Aggravated Assault

Arcbound Overseer

Umbral Collar Zealot

How it works

1. Activate Crystalline Crawler's second ability by tapping it, putting a +1/+1 counter on it.
2. Activate Umbral Collar Zealot by sacrificing Arcbound Overseer.
3. When Arcbound Overseer dies, it triggers, putting its +1/+1 counters on Crystalline Crawler.
4. Resolve the Umbral Collar Zealot ability.
5. Activate Crystalline Crawler's first ability five times by removing five +1/+1 counters from it, adding 3.
6. Activate Aggravated Assault by paying 3, causing you to untap all creatures you control and to get an additional combat and main phase after this one.
7. Declare Alesha as an attacker, triggering its ability, targeting Arcbound Overseer.
8. Activate Crystalline Crawler's first ability twice by removing two +1/+1 counters from it, adding W/BW/B.
9. Resolve the Alesha trigger, causing you to pay W/BW/B to return Arcbound Overseer from your graveyard to the battlefield tapped and attacking with six +1/+1 counters on it due to its modular ability.
10. Repeat.

This brilliant loop uses Umbral Collar Zealot to sacrifice Arcbound Overseer, triggering its modular ability to pile counters onto Crystalline Crawler. Once Crystalline Crawler is fully powered up by those counters and its own tapping ability, you can strip them away for the exact mana needed to fuel Aggravated Assault. That extra combat phase lets Alesha, Who Smiles at Death resurrect Arcbound Overseer directly from the graveyard while tapped and attacking, seamlessly feeding the sacrifice engine all over again.