Colfenor, the Last Yew + Gutter Grime + Altar of Dementia

Colfenor, the Last Yew

Gutter Grime

Altar of Dementia

How it works

1. Cast the creature card in your hand by paying 0.
2. Either that creature dies as a state-based action due to having zero toughness, or activate Altar of Dementia by sacrificing that creature.
3. Gutter Grime triggers, putting a slime counter on it and creating a X/X Ooze creature token.
4. Activate Altar of Dementia by sacrificing the Ooze.
5. When the Ooze dies, Colfenor triggers, returning the creature card from your graveyard to your hand.
6. If the Altar of Dementia abilities, milling target player a number of cards equal to the sacrificed creature's power each time.
7. Repeat.

This clever loop relies on Colfenor, the Last Yew to continuously recycle a 0-toughness creature from your graveyard while Gutter Grime scales your token army up to cosmic proportions. Each time your free creature dies, Gutter Grime triggers to grow a larger and larger Ooze token whose growing power fuels Altar of Dementia for an infinite mill win. When you finally sacrifice that massive Ooze to the Altar, Colfenor's trigger kicks in to fish your initial creature right back to your hand, ready to start the cycle anew.