Marneus Calgar + The Watcher in the Water

WUB identity

Commander legal

The 2 combo pieces

What must be in place

You have a way to draw a card during an opponent's turn.
You have a way to interrupt the loop after drawing your library.

How to execute it

  1. Draw a card during an opponent's turn by triggering Marneus Calgar using his activated ability, or by any other method.
  2. The Watcher in the Water triggers, creating a 1/1 Tentacle creature token.
  3. When the Tentacle enters the battlefield, Marneus Calgar triggers, causing you to draw a card.
  4. Repeat from step 2.
  5. After drawing any number of cards, interrupt the mandatory infinite loop by winning the game or removing a combo piece in response to a trigger.

What the combo produces