Mikaeus, the Unhallowed + Altar of Dementia + Lesser Masticore

Mikaeus, the Unhallowed
Altar of Dementia
Lesser Masticore

Requires
All permanents on the battlefield.
Steps
  1. Sacrifice the Lesser Masticore to Altar of Dementia to mill target player 2
  2. Lesser Masticore's persist and undying trigger
  3. Resolve the persist trigger returning Lesser Masticore to the battlefield with a -1/-1 counter
  4. Sacrifice the Lesser Masticore to Altar of Dementia to mill target player 2
  5. Lesser Masticore's persist and undying trigger
  6. Resolve the undying trigger returning Lesser Masticore to the battlefield with a +1/+1 counter
  7. Repeat
Results
Infinite mill. Infinite ETB. Infinite LTB. Infinite death triggers. Infinite sacrifice triggers.