Tarrian's Soulcleaver + Herd Baloth + Umbral Collar Zealot

Tarrian's Soulcleaver

Herd Baloth

Umbral Collar Zealot

How it works

1. Put a +1/+1 counter on Herd Baloth.
2. Herd Baloth triggers, creating a 4/4 Beast creature token.
3. Activate Umbral Collar Zealot by sacrificing the Beast.
4. When the Beast dies, Tarrian's Soulcleaver triggers, putting a +1/+1 counter on Herd Baloth.
5. Herd Baloth triggers, creating a 4/4 Beast creature token.
6. Resolve the Umbral Collar Zealot ability, putting a +1/+1 counter on it.
7. Repeat from step 3.

This ingenious loop transforms a simple +1/+1 counter into a self-sustaining engine by turning death into growth. It all begins when you place a counter on Herd Baloth, whose ability immediately births a 4/4 Beast token. You then feed that newly minted Beast to Umbral Collar Zealot, which sacrifices it to surveil 1 and conveniently grants the Zealot its own +1/+1 counter. As the Beast hits the graveyard, Tarrian's Soulcleaver triggers to place a fresh +1/+1 counter right back onto the Herd Baloth, restarting the entire cycle and leaving you with an unstoppable cascade of endless tokens, deaths, and library manipulation.