Fiend Hunter, Changeling Titan, and Mardu Siegebreaker

Prerequisites

• Fiend Hunter in hand or on the battlefield or in exile
• Changeling Titan in hand or on the battlefield or in exile
• Mardu Siegebreaker in hand or on the battlefield or in exile
• plus the mana cost of the creature in your hand available

Steps

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

Results

• Infinite creature ETB
• Infinite creature LTB