Changeling Titan, Mardu Siegebreaker, and All-Fates Stalker

Prerequisites

• Changeling Titan in hand or on the battlefield or in exile
• Mardu Siegebreaker in hand or on the battlefield or in exile
• All-Fates Stalker in hand or on the battlefield or in exile
• plus the mana cost of the creature in your hand available

Steps

1. Cast Changeling Titan for its mana cost
2. When Changeling Titan enters, it exiles Mardu Siegebreaker until Changeling Titan leaves the battlefield
3. Resolve any additional effects of Changeling Titan's ETB
4. When Mardu Siegebreaker leaves the battlefield, All-Fates Stalker is returned from exile to the battlefield
5. When All-Fates Stalker enters, it exiles Changeling Titan until All-Fates Stalker leaves the battlefield
6. Resolve any additional effects of All-Fates Stalker's ETB
7. When Changeling Titan leaves the battlefield, Mardu Siegebreaker is returned from exile to the battlefield
8. When Mardu Siegebreaker enters, it exiles All-Fates Stalker until Mardu Siegebreaker leaves the battlefield
9. Resolve any additional effects of Mardu Siegebreaker's ETB
10. When All-Fates Stalker leaves the battlefield, Changeling Titan is returned from exile to the battlefield
11. Repeat from step 2

Results

• Infinite creature ETB
• Infinite creature LTB