Alesha, Who Smiles at Death + Crystalline Crawler + Aggravated Assault + Arcbound Overseer + Ravenous Intruder

Alesha, Who Smiles at Death

Crystalline Crawler

Aggravated Assault

Arcbound Overseer

Ravenous Intruder

How it works

1. Activate Crystalline Crawler's second ability by tapping it, putting a +1/+1 counter on it.
2. Activate Ravenous Intruder by sacrificing Arcbound Overseer.
3. When Arcbound Overseer dies, it triggers, putting its +1/+1 counters on Crystalline Crawler.
4. Resolve the Ravenous Intruder 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 looping engine centers on Crystalline Crawler acting as a flexible mana producer, filtering the large pile of counters it receives whenever Arcbound Overseer is fed to Ravenous Intruder. By sacrificing the Overseer, you trigger its modular ability to dump a massive cache of +1/+1 counters straight onto the Crawler, which you then strip away for mana to fuel Aggravated Assault's extra combat steps. Meanwhile, Alesha, Who Smiles at Death takes advantage of those repeated combat phases to continually resurrect the Overseer from your graveyard, ensuring the sacrifice loop and its mana generation can run indefinitely.