Felidar Guardian + Karmic Guide + Altar of Dementia

Felidar Guardian
Karmic Guide
Altar of Dementia

Requires
Felidar Guardian in hand. All other permanents on the battlefield. 3w available.
Steps
  1. Cast Felidar Guardian by paying 3w
  2. Felidar Guardian's ability triggers, targeting Karmic Guide
  3. In response, activate Altar of Dementia by sacrificing Felidar Guardian, causing target player to mill a card
  4. Resolve Feldiar Guardian's trigger, blinking Karmic Guide
  5. Karmic Guide triggers, returning Felidar Guardian from your graveyard to the battlefield
  6. Repeat from step 2
Results
Infinite ETB. Infinite LTB. Infinite sacrifice triggers. Infinite death triggers. Infinite mill. Infinite self-mill.