Agatha's Soul Cauldron, Lurking Roper, and Shu Farmer

Prerequisites

• Agatha's Soul Cauldron on the battlefield
• Lurking Roper on the battlefield
• Shu Farmer in exile

Steps

1. During your precombat main phase, activate Lurking Roper using Shu Farmer's ability by tapping it, causing you to gain 1 life
2. Lurking Roper triggers, untapping itself
3. Repeat

Results

• Infinite lifegain
• Infinite lifegain triggers