Birgi, God of Storytelling // Harnfel, Horn of Bounty, Spellbinding Soprano, and Seething Anger

Prerequisites

• Birgi, God of Storytelling // Harnfel, Horn of Bounty on the battlefield
• Spellbinding Soprano in the graveyard
• Seething Anger in hand
• You have at least three opponents
• available

Steps

1. Activate Spellbinding Soprano's encore ability by paying and exiling it from your graveyard, creating a token copy of it with haste for each opponent you have
2. Declare each Spellbinding Soprano token as an attacker
3. Each Spellbinding Soprano token triggers, causing instant and sorcery spells you cast this turn to cost less to cast for each Spellbinding Soprano token
4. Cast Seething Anger with buyback by paying
5. Birgi triggers, adding
6. Resolve Seething Anger, giving target creature +3/+0 until end of turn and returning Seething Anger to your hand
7. Repeat from step 4

Results

• Infinitely powerful creatures until end of turn
• Infinite magecraft triggers
• Infinite storm count