Evolution Witness, Thran Vigil, and Birgi, God of Storytelling // Harnfel, Horn of Bounty

Prerequisites

• Evolution Witness on the battlefield
• Thran Vigil on the battlefield
• Birgi, God of Storytelling // Harnfel, Horn of Bounty on the battlefield
• You have a creature or artifact card in your graveyard
• You have a way to put a +1/+1 counter on Evolution Witness

Steps

1. Put a +1/+1 counter on Evolution Witness
2. Evolution Witness triggers, returning an artifact or creature card from your graveyard to your hand
3. Thran Vigil triggers
4. Holding priority, activate Harnfel by discarding an artifact or creature card
5. Resolve the Thran Vigil ability, putting a +1/+1 counter on Evolution Witness
6. Repeat from step 2

Results

• Infinite self-discard triggers
• Exile your library with the ability to play the exiled cards until end of turn
• Infinite +1/+1 counters on Evolution Witness