Karn, the Great Creator, and Aetherflux Reservoir

Prerequisites

• Karn, the Great Creator on the battlefield
• Aetherflux Reservoir on the battlefield

Steps

1. Activate Karn's first loyalty ability by putting a loyalty counter on it, causing Aetherflux Reservoir to become an artifact creature until end of turn
2. Give Aetherflux Reservoir lifelink
3. Activate Aetherflux Reservoir by paying 50 life, dealing 50 damage to any target and causing you to gain 50 life
4. Repeat step 3

Results

• Infinite damage
• Infinite lifegain triggers