Clever Impersonator, Karmic Guide, and Preston, the Vanisher

Prerequisites

• Clever Impersonator in your graveyard
• Karmic Guide in hand
• Preston, the Vanisher on the battlefield
• available

Steps

1. Cast Karmic Guide by paying
2. When Karmic Guide enters the battlefield, it triggers, returning Clever Impersonator to the battlefield from your graveyard
3. Choose not to have Clever Impersonator copy anything as it enters the battlefield
4. Clever Impersonator dies as a state-based action due to having zero toughness
5. Preston triggers, creating a copy of Clever Impersonator that is a 0/1 Illusion
6. Choose to have the Clever Impersonator token enter the battlefield as a copy of Karmic Guide
7. When the Clever Impersonator token enters the battlefield, it triggers, returning the nontoken Clever Impersonator to the battlefield from your graveyard
8. Repeat from step 3

Results

• Infinite creature tokens
• Infinite death triggers
• Infinite ETB
• Infinite LTB