Agatha's Soul Cauldron, Siren of the Silent Song, and Ioreth of the Healing House

Prerequisites

• Agatha's Soul Cauldron on the battlefield
• Siren of the Silent Song on the battlefield
• Ioreth of the Healing House in exile

Steps

1. Activate Siren of the Silent Song using Ioreth of the Healing House's ability by tapping it, untapping another creature you control that has a +1/+1 counter on it
2. Activate the other creature using Ioreth of the Healing House's ability by tapping it, untapping Siren of the Silent Song Siren of the Silent Song triggers, causing each opponent to discard and mill a card
3. Repeat

Results

• Infinite mill