Anticausal Vestige + Cloudstone Curio + Clever Impersonator

Anticausal Vestige

Cloudstone Curio

Clever Impersonator

How it works

1. Cast Clever Impersonator by paying its mana cost. Choose to have it enter as a copy of Anticausal Vestige.
2. When Clever Impersonator enters, Cloudstone Curio triggers, returning Anticausal Vestige from the battlefield to your hand.
3. When Anticausal Vestige leaves the battlefield, it triggers, causing you to draw a card and and put Anticausal Vestige from your hand onto the battlefield.
4. When Anticausal Vestige enters, Cloudstone Curio triggers, returning Clever Impersonator from the battlefield to your hand.
5. When Clever Impersonator leaves the battlefield, it triggers, causing you to draw a card and put Clever Impersonator from your hand onto the battlefield as a copy of Anticausal Vestige.
6. Repeat from step 2.

This fascinating loop relies on Clever Impersonator entering as a copy of Anticausal Vestige, turning your permanent types into a revolving door of triggers. Every time one of them enters the battlefield, Cloudstone Curio senses a nonartifact permanent arriving and bounces the other copy back to your hand. As the bounced permanent leaves the battlefield, Anticausal Vestige's leaving-the-battlefield ability triggers to draw you a card and immediately cheat that very card back onto the battlefield tapped, keeping the entire engine running infinitely.