Thopter Foundry, Sword of the Meek, Devoted Druid, and Rosie Cotton of South Lane

Prerequisites

• Thopter Foundry on the battlefield
• Sword of the Meek on the battlefield
• Devoted Druid on the battlefield
• Rosie Cotton of South Lane on the battlefield

Steps

1. Activate Devoted Druid's first ability by tapping it, adding
2. Activate Thopter Foundry by paying and sacrificing Sword of the Meek, creating a 1/1 Thopter artifact creature token and causing you to gain 1 life
3. When the Thopter enters, Rosie and Sword of the Meek trigger
4. Resolve the Rosie trigger, putting a +1/+1 counter on Devoted Druid
5. Resolve the Sword of the Meek trigger, returning it from your graveyard to the battlefield attached to the Thopter token
6. Activate Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it
7. Repeat

Results

• Infinite ETB
• Infinite creature tokens
• Infinite lifegain
• Infinite lifegain triggers