Altar of Dementia + River Kelpie + Thran Vigil

UB identity

Commander legal

The 3 combo pieces

How to execute it

  1. Activate Altar of Dementia by sacrificing River Kelpie.
  2. When River Kelpie dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
  3. Thran Vigil and River Kelpie trigger.
  4. Resolve the Thran Vigil trigger, putting a +1/+1 counter on River Kelpie.
  5. Resolve the River Kelpie trigger, causing you to draw a card.
  6. Resolve the Altar of Dementia ability
  7. Repeat.

What the combo produces