Anticausal Vestige + Cloudstone Curio + Undercover Operative

Anticausal Vestige

Cloudstone Curio

Undercover Operative

How it works

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

This clever loop turns a pair of shape-shifting creatures into an endless cycle of departures and arrivals, all anchored by Cloudstone Curio's watchful presence. By having Undercover Operative enter the battlefield as a copy of Anticausal Vestige, the Curio treats both permanents as sharing the creature type and triggers to bounce the original. When that original Anticausal Vestige leaves the battlefield, its triggered ability lets you drop it right back onto the battlefield, which in turn triggers Cloudstone Curio to bounce the disguised Undercover Operative back to your hand. As the Operative re-enters once more to copy the Vestige, the cycle repeats indefinitely, continuously drawing cards and cycling permanents through play.