Worldgorger Dragon, Fiend Hunter, and Changeling Titan

Prerequisites

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

Steps

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

Results

• Infinite creature ETB
• Infinite creature LTB
• Infinite blinking of permanents
• Infinite mana lands you control can produce