Thopter Foundry, Sword of the Meek, and Carnival of Souls

Prerequisites

• Thopter Foundry on the battlefield
• Sword of the Meek on the battlefield
• Carnival of Souls on the battlefield
• available

Steps

1. Activate Thopter Foundry by paying and sacrificing Sword of the Meek, causing you to create a 1/1 Thopter artifact creature token and gain 1 life
2. When the Thopter enters the battlefield, Carnival of Souls and Sword of the Meek trigger
3. Resolve the Carnival of Souls trigger, adding and causing you to lose 1 life
4. Resolve the Sword of the Meek trigger, returning it from your graveyard to the battlefield attached to the Thopter
5. Repeat

Results

• Infinite ETB
• Infinite lifegain triggers
• Infinite creature tokens