Changeling Titan, Lagrella, the Magpie, and All-Fates Stalker

Prerequisites

• Changeling Titan in hand or on the battlefield or in exile
• Lagrella, the Magpie 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 Lagrella until Changeling Titan leaves the battlefield
3. Resolve any additional effects of Changeling Titan's ETB
4. When Lagrella 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, Lagrella is returned from exile to the battlefield
8. When Lagrella enters, it exiles All-Fates Stalker until Lagrella leaves the battlefield
9. Resolve any additional effects of Lagrella'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