Bloodsoaked Champion + Altar of Dementia + Pitiless Plunderer + Pawn of Ulamog

Bloodsoaked Champion
Altar of Dementia
Pitiless Plunderer
Pawn of Ulamog

Requires
All permanents on the battlefield. You attacked with a creature this turn.
Steps
  1. Activate Altar of Dementia by sacrificing Bloodsoaked Champion
  2. When Bloodsoaked Champion dies, Pitiless Plunderer and Pawn of Ulamog trigger
  3. Resolve the Pitiless Plunderer trigger, creating a Treasure artifact token
  4. Resolve the Pawn of Ulamog trigger, creating a 0/1 Eldrazi Spawn creature token
  5. Resolve the Altar of Dementia ability, causing target player to mill cards equal to Bloodsoaked Champion's power
  6. Activate the Treasure by tapping and sacrificing it, adding b
  7. Activate the Eldrazi Spawn by sacrificing it, adding c
  8. Activate Bloodsoaked Champion by paying 1b, returning it to the battlefield from your graveyard
  9. Repeat
Results
Infinite ETB. Infinite LTB. Infinite death triggers. Infinite sacrifice triggers. Infinite mill. Infinite self-mill.