Tribute to the World Tree + Lesser Masticore + Altar of Dementia

Tribute to the World Tree

Lesser Masticore

Altar of Dementia

How it works

1. Activate Altar of Dementia by sacrificing Lesser Masticore.
2. When Lesser Masticore dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. When Lesser Masticore enters the battlefield, Tribute to the World Tree triggers, putting two +1/+1 counters on Lesser Masticore .
4. Resolve the Altar of Dementia ability from step 1, causing target player to mill cards equal to Lesser Masticore's power.
5. Repeat.